The Chinese don't change their name.   In Chinese culture, the wife never truly belongs to the family, she's always an outsider and so is her side of the family.    But anyone can change their name at any time if they want, its just the Chinese don't and its not really supported by the government.

As for a foreigner I'm not sure.  I read somewhere you have to have been in China for five years and married for 3 but I'm not sure how true that is.   You're not a Chinese citizen so I'm guessing you wouldn't go through the same procedures a Chinese would.   Your passport is your ID so I'm pretty sure you would have to go home to change your name.

It is your home country's law that matters on this.

I am sure most countries will let you change your surname to your husbands surname.

I want to change my name to Won Hung Lo.,,,if you don't know the joke,,say it out loud

To our law ,It's ok for the citizen to take either  father's or mother's surname ,but the law seems not  mention if girl can take the husband's surname ,I think it is OK,because in ancient times of China,when girls get married,they will and must follow their husbands' surname.

After the great revolution and women liberation movement, if you know modern Chinese history, wives can choose their own name.Of course you can take your husband's surname if you like.It is your home country's law that matters on this, as mikael84  said.Say,my wife didn't take my surname,we are still trying to raise child and make our life better.

How should I know?

not a good idea for the children though, possibly you also, 85 percent of china had the same 100 last names , so going to the bank , using fingerprints, eye scans , codes , all have to be increased. having 20 kids in one grade with surname wang is a pain in the ass as well,

seven percent of china population have last name wang , 92 million people, i think i would want to be a little unique, in america i would not want a last name of smith or jones either.