ObjectiveTo evaluate the effective cleaning methods for complex medical instruments, improve the cleaning quality, ensure sterilization effect， and control nosocomial infection . MethodsFive hundred pieces of moderately contaminated medical instruments recycled from central sterile supply department were divided into two groups, each group included 150 pieces of sawshaped instruments and 100 pieces of lumen instruments; Observation group performed hand washing and multienzyme ultrasound machine cleaning method, control group adopted hand washing with flowing water, the cleanliness and positive rates of occult blood test (OBT)of two groups after cleaning were compared .ResultsThe qualified rate of cleanliness of sawshaped and lumen instruments after cleaning in observation group was 98.67% and 98.00% respectively, the positive rate of OBT was 0.67% and 1.00% respectively; The cleanliness of sawshaped and lumen instruments after cleaning in control groups was 78.67% and 70.00% respectively, the positive rate of OBT was 28.67% and 34.00% respectively (P<0.01); The efficacy of cleaning method in observation group was obviously superior to that in control group. ConclusionCombination of hand and multienzyme ultrasonic cleaning can improve the cleaning quality of complex medical instruments.