In general, it is required to deposit funds in US dollars. As upstairs said, foreign exchange margin trading is not fully open in China at present, and customers are all overseas investors, so banks can't be domestic banks, but all foreign banks, so they are generally settled in US dollars. Moreover, the entire foreign exchange market is based on the US dollar, so it is required to deposit US dollars.

However, you may need to pay more attention to the platform that says you can deposit money in RMB. You can find out whether this platform is formal first, and then it will tell your bank whether it has credibility. After these are clear, if it is a formal platform, what he means by RMB deposit should mean that after you remit RMB, the bank will automatically convert it into US dollars according to the exchange rate of the day to calculate the deposit. This may be to attract customers or to make them more convenient.

At present, most foreign exchange companies deposit by credit card and wire transfer. In fact, if you don't have a credit card and dollars, I suggest you go to the bank to exchange them and save your own money. It is more realistic to operate by yourself.

Finally, regardless of any deposit method, the most important thing is to understand the security of platform funds, which is the key!