Objective Secondary infection with pseudomonas aeruginosa( PA) in diabetic foot ulcer( DFU) was analyzed to investigate the related risk factor, antibiotic resistance, and prognoses of the infection. Methods Pathogen cultures were carried out in 966 DFU patients with their clinical data collected. All of the patients were followed-up for two years to observe the outcomes, including ulcer healing, amputation, recurrence of ulcers, non-fatal cardiovascular events, and death. The antibiotic susceptibility, risk factors and associated outcome of secondary PA infection were analyzed. Results Total incidence of PA infection was 13. 0％ in DFU patients, of which 38. 1％was secondary. The susceptibility rates of secondary infected PA to tobramycin, meropenem, eftazidime, levofloxacin, cefepime, and cefepime were similar to those in primary infected PA. However, the susceptibility rates of secondary infected PA to piperacillin, piperacillin/tazobactam, ciprofloxacin, imipenen, gentamicin, aztreonam, and amikacin decreased by 12％ to 22％ as compared with primary infected PA. The healing rate was much lower in patients with secondary PA infection compared with those with primary PA infection, and the accumulated healing rates at2yearswere44.44％ and70.4％ (P=0.01) respectively. Theriskofulcerhealingfailurewithintwoyears increased by 3 folds in patients with secondary PA infection. After adjusting for age, sex, Wagner grade, infection grade, and duration of DFU, plasma albumin level was an independent risk factor for secondary PA infection in patients with DFU(P=0. 001). Conclusions The antibiotics susceptibility rates of secondary infected PA were lower than those of primary infected PA. Secondary PA infection in DFU was less likely to be healed. Plasma albumin level was a risk factor for secondary PA infection.