Objective To find out the influencing behavioral factors of antibiotics usage in population in Lanzhou. Methods Status of antibiotics usage was investigated in four hospitals in Lanzhou. Results The self-medicine pro portion among patients with respiratory system infection, infectious di arrhea, urinary system infection and choleic system infection were 44.22%, 31. 76%, 22.07% and 6.61% respectively. Patients having higher income used some antibiotics at a middle price, while patients having lower income used antibiot ics at a lower price. The educate d person applied some antibiotics at a lower price, but the illiterate person us ed some antibiotics at a higher price. The combined usage of antibio tics was affected by the disease program and distance of seeing doctor. The fart her distance away from hospital, the more proportion of antibiotics(two or thre e) used combinedly. Conclusions The antibiotics usage was affe cted by the disease variety, disease program, distance to hospital, average inco me and educ ated level.