Abstract: Objective To observe the etiological characteristics of nosocomial infection in Rheumatiod Arthritis and take positive prevention action.Methods A total of 1020 patients with RA were studied who were admitted to GuangHua Hospital between June 2008 and September 2009. Their basis information and cases feature were registered in detail. The items for analysis included patient's age, gender, medicine for treatment, leucocyte count, lymphocyte count, ESR, CRP etc.Results Of the 1020 patients investigated, 824 were female, and 196 male. Both female and male patients ranged in age from 17 to 92 years old, with their average age being 48 years old, and disease course 8.47 years. There were 316 patients who suffered from nosocomial infecton, of whom 272(the infection rate,33.01%) were female and 44 male(22.45%), the infection rate being 30.98%.As to affected sites and occurrence rate, in urinary tract, upper and lower respiratory tracts and vagina,infection accounted for 94.04% of the total. And 304 pathogens were isolated, of which Gram-negative bacteria were 172, Gram-positive 100, mycotic 7 and chlamydial 102, accounting for 43.99%, 25.88%,4.34% and 26.09% respectively.Conclusion The nosocomial infection in RA was much higher than the average level, higher in female than in male, and chlamydial infection held a higher level than other diseases. Pathogenic spectrum changed year by year.