Undergraduate research (UR) refers to a series of scientific research activities for undergraduates. For the past few years in China, medical colleges and universities have increasingly attached importance on UR, aiming to provide undergraduates with better scientific research conditions, improve their understanding about scientific research and their basic scientific skills. Chinese medical undergraduates participate in scientific research spontaneously. However, the specific effects of UR are still unclear. In China, few quantitative standards to evaluate the detailed roles and effects of medical undergraduates' UR are available yet. To explore how UR influences Chinese medical undergraduates' scientific research abilities and their individual development, we conduct a cross-sectional analytical study by anonymous self-administered questionnaires. The questionnaires access the scientific research capabilities and qualities of students. The results show that students who participate in UR are equipped with better self-evaluation of designing research projects, using statistical software, making figures and charts, evaluating experimental results and performing experiments than those who do not; and the students who persist in UR have the highest self-evaluation on the abilities mentioned above. Hence, through quantitative criteria, it can be concluded that UR can help Chinese medical undergraduates build interest in scientific research, develop scientific thinking and basic research capacities, and set a solid foundation for future research.