Psychrotrophic bacteria of raw milk can produce a large amount of heat resistance lipase,which causing raw milk putridity significantly.Thus our main purpose in this dissertation was to isolate high lipase-produced psychrotrophic bacteria from milk and identify them by using the SHERLOCK(A)(R) microbialidentification system of American MIDI corporation.Therefore,these researches would provide a basic understand in avoiding negative influences of psychrotrophic bacteria in raw milk.We used the improved LA culture as screening psychrotrophic bacteria culture and isolated 30 strains of psychrotrophic bacteria from 40 raw milk samples.