Objective　To evaluate the value and feasibility of Microsim medical simulation training system in medical students' clinical thinking training. Method　96 students of 5-year program of medicine of Grade 2009 and Grade 2010 were the research object. These students were randomly divided into two groups (group A: After 3 weeks' clinical practice in respiratory medicine

taking 1 week Microsim training. group B: Taking 4 weeks clinical practice in respiratory medicine. Each group has 48 students.). The examination and teaching satisfaction of the two groups were observed after the end of the internship. SPSS 17.0 statistical software was used to analyze the collected data (measurement data matching t test

counting data by chi-square test). Results　The Microsim system score: group A was (89.37±7.18)

group B was (61.95±15.34). The difference between groups was statistically signifi-cant. The following scores suggested the assessment of students' ability of clinical thinking: ability to analyze problems [group A (89.95±4.02) vs. group B (75.51±6.34)]

the ability to deal with the prob-lem [group A (78.81±8.09) vs. group B (59.67±9.33)]

treatment scheme [group A (86.74±6.59) vs. group B (70.39±7.05)] and the treatment effect [group A (88.61±8.16) vs. group B (63.54±11.48)]. In these aspects

the two groups had statistically significant difference

but communication [group A (82.47±5.23) vs. group B (84.09±3.72)] had no statistically significant difference between the two groups. 89.6% (43) of the participants believed that the Microsim medical simulation training system could significantly improve the clinical thinking ability

but only 58.3% (28) of the students believed that the basic theory of knowledge could be consolidated. Conclusion　Microsim medical simulation training system can improve the students' ability of clinical thinking and clinical comprehensive treat-ment ability. It can be used as an effective complement to clinical practice teaching.