Abstract: Objective To explore the application effect of formative assessment in standardized resident training of Thoracic Surgery. Methods A total of 60 residents who attended the Department of thoracic surgery from Jan to Jun 2019 during surgery resident standardized training in The First Affiliated Hospital of University of Science and Technology of China were selected as subjects and randomly divided into observation group and control group, with 30 in each group. After the Thoracic Surgery training, training effect was evaluated by examination and questionnaire survey. Results The scores of theoretical examination(91.57 ±3.09 vs. 87.87±3.20) and skill examination(91.17±2.35 vs. 86.93±2.38) in observation group were higher than those of control group. The difference was statistically significant(all P<0.05). The ability of self-learning、 clinical thinking, clinical operation and evaluation teaching methods were higher than those of control group, the differences were statistically significant(all P<0.05). There was no significant difference between the two groups in the ability of communication(P>0.05). Conclusion Formative assessment used in thoracic surgery training during surgery resident standardized training is beneficial to improve training effect and the quality of teaching.