How to address English person?

I come from a small town in China. Recently I need to do business with Americans. How to address them politely. For example his name is Bill Gates, do I call him Mr Bill or Mr Gates or Mr Bill Gates?

Mr Bill would be an informal greeting amongst old friends.
Mr Bill Gates would be a bit overdone . . .
Best is Mr Gates for normal business.
Mr for gentleman, Miss for lady unless you know she is married , then it is Mrs. for married lady.
For regular business just use the Mr or Miss and last name.
Good luck with your business ventures !

I would suggest using "Mr. Gates". "Mr Bill" would sound strange to most English speakers. Using "Mr Bill Gates" would probably make them think that they were receiving a solicitation of some sort.

If you want to address them formally then it is:

Mr {last name}

or

Ms {Last name} for a female.

If you want to address them informally then it would just be {First name}

If addressing him in person, use Mr Gates, unless he tells you to call him Bill.

In a formal letter, address as either Mr Bill Gates, Mr B Gates, or just Mr Gates. any of those is acceptable.

never call him Mr Bill. this is very strange to english speakers.