Best thing is to go to a travel clinic with your itinerary. When we went to china we only needed to make sure our immunizations were up to date, including hep a&b and tetanus. Certain places may need yellow fever, however not usually in the tourist, non- rural spots about 6 years ago
Irene, check with your doctor, but nothing special required. However - The World Health Organization (WHO) recommends all travellers should be covered for, Diphtheria, Tetanus, Measles, Mumps, Rubella, and Polio (the routine shots you should've got as a child). Tetanus and DipHtheria require booster shots every 10 years. Vaccination against Hepatitis A and B is also wise.
If you are travelling to remote rural areas you should consider vaccination against Typhoid, TB, Cholera and Japanese Encephalitis. Although cases among travellers are rare, there are outbreaks from time to time. Rabies is quite high in China, so take care around domestic animals too.
Worldnomads have some other tips too, here:
Phil from the Safety Hub about 6 years ago