I'm an economics student, and as far ast my university, students in this department start job-hunting earlier.

I don't know howwhat the situation is like inat other universityies, though.

Or “I don't know the situation at other universities though."

We can earn a bachelor's degree in four years, and then 90 percent of economics students enter a company rather than staying at universityto start working rather than continuing to graduate school.

Also, it is not uncommon they arfor them to be accepted by some companies in their third year.

However, companies might want to secure talented new employees more quickly than other companies, and students also want to secure their job quickly, and this seemswhich seems to have led to a trend thatwhere students are starting their job hunting earlier and earlier.

It sounds more natural to have a cause/effect type preposition corrector here for example "which” or "so" rather than just "and"

I'm an economics student, and as far as my university goes, students in this department start job-hunting earlier.

I don't know howwhat the situation is like in other universityies though.

Moreover, byat the beginning of the third year of a bachelor's degree, many economics students begin some kind of activity for their job-hunting.

Also, it is not uncommon that they are accepted by some companies in their third year.

"that" can be omitted for causal speech.

So, even though I am attending a four-year university, the period during which we are truly "just university students" lasts only about two years.

However, companies might want to secure new talented new employees more quickly earlier than other companies, and students might also want to secure their jobs quickly, and this seems to have led to a trend that students are starting their job hunting earlier and earlier.

I'm an economics student, and as far as my university is concerned, students in this department start job-hunting earliery.

Adding "is concerned" help the sentence flow better. Changing "earlier" to "early" makes more sense because there was no comparison made. An alternative sentence with "earlier" could have been "...students in this department start job-hunting earlier than other students"

I don't know how the situation is like in other universityies though.

However, companies might want to secure talented new employees more quickly than other companies, and students also want to secure their jobs quickly, and this seems led to a trend that students are starting their job hunting earlier and earlier.

cCollege student for only two years

I'm an economics student, and as far ast my university, students in this department start job-hunting earlier.

I don't know how the situation is like in other universityies though.

We can earn a bachelor's degree in four years, and then 90 percent of economics students enter a company rather than staying atin university.

"Stay at" means to remain in the university physically. On the other hand, "stay in" means to continue studying in the university.

Moreover, by the beginning of the third year of a bachelor's degree, many economics students begin some kind of activity for their job- hunting.

(1) 何らか: some kind of; some form of; some sort of.
(2) In the last sentence, you did not hyphenate "job hunting". Hence, for consistency, I have removed the hyphen here.

Also, it is not uncommon they arfor them to be accepted by some companies in their third year.

A common construction is "it is not uncommon for A to B".

However, companies might want to secure talented new employees more quickly than other companies, and students also want to secure their jobs quickly, andso this seems to have led to a trend thatwhere students are starting their job hunting earlier and earlier.

(1) I replaced the second "and" with "so" to introduce more variety in the vocabulary. This might help the sentence feel less stiff.
(2) Since you are talking about students in general, the plural "students" seems natural here. And since more than one student implies more than one job, I've also used the plural "jobs".

I'm an economics student, and as far ast my university, students in this department start job-hunting earliery.

"earlier" is probably better used for a comparison (where you specify earlier than whom).

I don't know howwhat the situation is like in other universityies, though.

Since you're talking about multiple universities, it should be plural.

We canIt usually takes around 4 years to earn a bachelor's degree in four years, and then 90 percent of economics students enter a company rather than staying at university.

Phrasing it as a potential feels a little strange to me, so I tried rewording it to keep the same general meaning.

Moreover, by the beginning of the third year of a bachelor's degree, many economics students begin some kind of activity for their job-hunting.

"activity" here feels a bit redundant - we'd usually just say that they begin job-hunting

Also, it i's not uncommon that they are accepted by somea companiesy in their third year.

A lack of contractions sounds fairly unnatural in English, unless you are really trying to emphasise a point it's probably better to use them.

However, companies might want to secure talented new employees more quickly than other companies, and student also want to secure their job quickly, and this seems to have led to a trend that students are starting their job hunting earlier and earlier.