It will depend on which province, which city within that province, her relatives, the local PSB, your employer etc. etc. etc.

It is illegal throughout China and considered immoral by most but tolerated by some.

The main problem would be, you can't purchase property unless a Chinese Citizen owns 50%. You can rent, but not buy. If you cannot work legally in China and your age is over 60, then you will be required to have a medical once a year and most all illnesses they will ask you to go back to your home country to be treated.
The living with a Chinese woman. Depends on age, if you're older looking for a younger woman, you'll eventually create problems for both of you. If you're looking for a woman your age, then it's really possible, they have no living relations to presure them into a traditional state of mind but still Xielias, if you love her, why not marry her

Be careful, she will probably be a spy for the PSB who will share everything they learn with the FBI and CIA. lol

Duplicate?

a tricky situation big boss......... ! as you are planning to stay its pretty difficulty well give it a try....... woman you can find them...... love shall come with money as well........... if you are daddy with bucks welcome to lala land than.......... as for person of your age i will tell you be in your own country and enjoy time with your own people i am sorry if that do not hurt your feelings respectively..... life is unpredictable anything can happen so i hope at the end you do not regret your life.........

Godspeed

I still don't understand why you would post this here. You should keep this secret, just makes the rest of us foreigners look bad.

the real question should be, is it socially acceptable for you to live with whom you love regardless of external reasons? do you love him? are you willing be with whim no matter who says what? then go ahead and never look back