By UnionPay account, I assume you mean a Chinese bank account like Bank of China or such.  If so, the answer is legally, no.  Unless it is a business account, then it is okay legally.

If it isn't a business account, then you would be committing tax fraud.  

If you get too many payments to your private account from outside the country, the China tax people will start to get nosey and you really don't want that.

Now... You might want to think about going to Hong Kong and opening an offshore account there at HSBC or some other bank.  You can setup a multi-currency account and get an ATM card that will allow you to withdraw money from the RMB portion of that account here in China.

As a side note, the HSBC in Hong Kong (and the rest of the world) have almost no connection to the HSBC in mainland China. So don't expect to be able to manipulate your account (or withdraw money free) from an HSBC bank here.

Thankfully, HSBC in Hong Kong has a pretty cool online banking service that will allow you to manipulate your accounts as much as you desire.

I've got a HSBC (UK account) and I transfer money almost every month from that to a Bank of China account in sterling. Never had any problems yet and we've been doing this for the best part of two years.

I havent done this but i have asked a bank ( Merchant Bank of China ) about it and they say it can be possible, so I think the same can be true to all banks, just approach one and ask, go to the agricultural bank of china or ICBC