Background: More and more medical schools in China start to use problem-based learning(PBL) throughout their education, therefore, the evaluation on the effective- ness of PBL becomes extremely improtant. Objective: To establish an assessment system of PBL curriculum which is a suitable for Chinese student characteristics and education system, and to assess the effectiveness of PBL curriculum. Methods: 93 students in grade 4 and 89 in grade 3 were involved in this group control study and before-after study. Self-assessment scales was used to assess the effectiveness of PBL curriculum. the reliability and validity of Capacity Assessment Scale were tested by Cronbach s a coefficient and correlation coefficient method respectively. From the first timepoint to the second timepoint, an independent samples t test was used to analysis the difference of ability between grade 4 and grade 3 students, and the difference of student self-assessment, peer assessment and instructor ratings in grade 4 and grade 3 students. Results: Cronbach s a coefficient of Capacity Assessment Scale was 0.810, Pearson correlation coefficients between 0.4 0.7. The professional quality, the role of awareness, analytical reasoning ability, information management capacity, communicative capability of the grade 3 and 4 students Involved in PBL curriculum had statistically significant difference between the first and second timepoint (P & 0.05). From the first timepoint to the second timepoint, there was no significant difference (P = 0.310 and 0.506, respectively) in self-assessment and student peer assessment of 93 students in grade 4, and a statistically significant difference (P&0.001) in instructor ratings; there was a statistically significant difference (P & 0.001, respectively) in self-assessment and instructor ratings of 89 students in grade 3, and no statistically significant difference (P = 0.116) in student peer assessment. Conclusion: Competency Assessment Scale is designed rationally, and its reliability and validity is in a high level. This scientific assessment system can improve the accuracy of the evaluative results. PBL curriculum can improve the professionalism, role awareness, analytical reasoning ability, information management capacity, the communicative capacity of student. At the same time, early propaganda of PBL ideological can improve the effectiveness of PBL curriculum.