Based on the organization resources theory， this paper investigates the impact mechanism of relative resources power function on audit quality and gives the empirical evidence when there does not exist social ties between auditors and clients. Under the perspective of organization resources， the impact mechanism of social capital matching on audit quality is a power mechanism， information mechanism and reputation self-protection mechanism. Empirical results show that， auditors’ relative social capital to clients is positively associated with audit quality. Specifically， the greater auditors’ political social capital and business social capital to clients are， the better auditors’ audit quality will be. Clients’ political social capital， however， also impairs the audit quality. The results provide both theoretical reference and empirical evidence on the future research on the economic effect of social capital matching in auditing.