We examine whether auditors' participation in CPA associations and social network organizations (i.e. Lions Club and Rotary Club) influence its audit quality. The empirical results show that auditors who join more CPA associations and social network organizations can effectively suppress earnings management. Further tests explore whether the incremental effect exists for non-Big 4 auditors, and we find that the results support our hypothesis. Moreover, this study conducted robust tests and additional tests, and find the same evidence to support our main results.