Objective:To explore whether working memory span training can expand working memory capacity.Methods:A randomized controlled trial design was adopted and a total of 60 healthy college students were recruited and randomly divided into training group ( n=30, receiving adaptive training of spatial breadth task) and control group ( n=30, receiving non-adaptive training of low difficulty spatial breadth task). The cognitive behavior and event-related potential (ERP) data of all subjects when completing the change awareness task were collected before and after training.The SPSS 22.0 statistical software was used for data analysis. The differences between the training group and the control group before and after training were compared by repeated measurement analysis of variance. Results:Repeated measurement ANOVA showed that there were significant time and group interactions at the levels of cognitive behavior(K score, F=5.352, P=0.025) and ERP (CDA, F=4.644, P=0.037) levels. Further post test found that compared with pre-training (pre-test), the K-score ((0.51±0.93), (1.61±1.07), F=26.81, P<0.001) and CDA ((-1.49±1.07)μV, (-2.03±0.94)μV, F=4.731, P=0.041) of the training group increased significantly after training (post-test), and there was no significant difference in K-score and CDA of the control group before and after training (boh P>0.05). Conclusion:Working memory span task can be used as an effective training paradigm to improve working memory capacity.