I am goplanning to purchase US$ 10001,000 USD this morning, so I just checked the currency exchange rate of US$D to CNY (Chinese Money) just nowyuan).

You use "going to" when you're 100% sure you're going to do something. But let's say the exchange rate was horrendous, then you might have changed your mind and not have gotten your money exchanged. Hence, the change from "going to" to "planning to." I also reformatted the money expressions to reflect the usage I see more often.

It remains high ast 7.30 from the Dollar to CNYCNY per USD.

The rate fromexchange rate between CNY toand the US Dollar has fluctuated inD has been fluctuating over the past few years.

It's still fluctuating so "has been fluctuating" is better. "Over the past few years" also better communicates the continuity.

At the first Initially, when the rate started to dropping, we were afraid CNY wouldfeared the CNY might devalue to 7, 8, andor even to 10.

"afraid" is also okay, but "feared" might convey the direness of the situation better.

Later, as Ifter discusseding with my friends and made, we reached a consensus that the CNY wouldn't fall below 7.35.

"reach a consensus" is the proper expression. You can't reach a consensus without first finishing a discussion.

I madetook a screenshot of the line graph, in which can be seen that beginnshows that starting from February this year, the US$D has been on an upward trend.

The proper expression is "took a screenshot." I fixed the rest of the sentence to make it more natural sounding and grammatically correct.

While I believe the CNY rate can be controlled by the government to a certain degree.

While is often used as a conjunction, using it with just one independent clause is awkward. (<- Example of the usage of "while") I added "to a certain degree" to better communicate the reality of economics.

However, I also deem it's impossiblebelieve it's unlikely for thate CNY will have the capability to challenge the US$D in the next 20 years.

Using "believe" here improves the flow of the paragraph. "Impossible" sounds way too definite and probably can only be made after extensive research as a skillful economist.

I am going to purchase US$ 1000$1000 USD this morning, so I checked the currency exchange rate of US$ to CNY (Chinese Money) just now.

"$1000 USD" is how I have seen it written most often, but it might be stylistic.

It remains high ast 7.30 from the Dollar to CNY.

At the first dropping, we were afraid CNY would devalue to 7, 8, andor even to 10.

It would be one of those three values and not all of them, so you would use "or"

Later, as I discussed with my friends and I made a consensus that CNY wouldn't fall below 7.35.

The first one is a little awkward, but okay.

I made a screenshot of the line graph, in which it can be seen that beginning from February this year, the US$ has been on an upward trend.

While I believe the CNY rate can be controlled by the government.

Or "While I believe the CNY rate can be controlled by the government, [I also believe...]"