ObjectiveTo explore the teaching effect based on the teaching of clinical thinking in  diagnostics probation teaching for medical undergraduates. MethodsA total of 108 third-year clinical medicine undergraduates who studied Clinical Diagnostics at Xiangya Hospital of Central South University from March to July 2017 were selected. According to the principle of cluster sampling, 2 small classes of a total of 56 students were randomly selected and divided into two groups including the control group and the experimental group. They all received the same theoretical teaching of diagnostics at the same time. The 28 cases in the experimental group received clinical thinking teaching during the diagnostics probation, while the 28 cases in the control group received traditional teaching during the diagnostic probation. Final diagnostic tests, competitions and questionnaire surveys were used to evaluate the diagnostics learning effects of the two groups. The results of internal medicine tests and admission condition for master′s degree candidates of the two groups were followed up and compared. ResultsThe total score of diagnostic tests in the experimental group ［（82.01±6.35）points］ was better than that of the control group ［（74.25±9.46）points］, the difference was statistically significant （t=3.60, P＜0.01）. Compared with the control group （15,6）, there were no significant differences （χ2=2.80, 1.40, all P＞0.05） in the number of participants and winners in the diagnostic teaching competition of the experimental group （21, 10）. The total score of feedback evaluation in the experimental group ［（94.75±4.04）points］ was higher than that of the control group ［（81.03±4.83）points］, and the difference was statistically significant （t=11.53, P＜0.01）. The total score of internal medicine test in the experimental group ［（82.76±7.63）points］ was better than that of the control group ［（74.52±9.75）points］, and the difference was statistically significant （t=3.52, P＜0.01）. There were no statistically significant differences in the admission condition for master′s degree candidates （23, 20） and the admission condition for master′s degree candidates of "double tops" construction universities （21, 18） in the two groups （χ2=0.90, 0.02, all P＞0.05）. ConclusionCarrying out clinical thinking teaching in diagnostics probation for medical undergraduates can improve the teaching effect of diagnostics and may affect the effect of continuing learning.