Pseudomonas aeruginosa (118 strains) from Xian were typed by 12 groups O-serum and revised pyocin typing method Results indicated that VI, I, III were major serotypes, VI type were mainly from trauma infected, I type mainly from respiration system infected. Pyocintype were mainly I and UT types. Pyocintype I were mainly 1/c and 1/x subtypes. 85.7% of 1/c subtypes were serotype VI, 84.4% of 1/x subtypes were serotype I.