Abstract: OBJECTIVE To observe the cleaning effects by different methods for longtime stored and severely polluted luminal devices, so as to determine the best pre-treatment cleaning method, and improve the cleaning and disinfection quality of luminal devices. METHODS A total of 360 severely polluted luminal devices which were stored more than 3 hours in Jun 2015 were randomly divided into 3 groups, with 120 pieces in each group, and were conducted pre-cleaning by different processes. Ultrasonic cleaning pre-treatment were used for group A, hand-washing pre-treatment were used for group B, and no pre-treatment were used for group C. cleaning of surgical instruments procedure was used by putting devices with different pre-treatment into automatic cleaning sterilizer. All the data were randomly selected and compared by visual test with the help of magnifier with light source and ATP bio-luminous detector after the cleaning procedures. RESULTS Qualified rates for group A, B, and C were 95.8%, 86.7%, and 66.7%, respectively. The cleaning effect for group A was the best, which was much better than that of group B and C (P＜0.001). In group A, the time was 7 min, the cost was 18 yuan, while in group B, the time was 35 min, the cost was 20 yuan. CONCLUSION It is necessary to conduct pre-treatment for longtime dried luminal devices before putting into automatic cleaning sterilizer. USC could be the first choice for pre-treatment on medical devices' cleaning.