This research examines the issue that the communication effectiveness of companies providing professional audit services (connective communication style, social dialogue and information provision), social cognitive capital and rapport established between an auditor and small and medium companies(SME) client are instrumental in influencing the latter’s evaluation of the technical quality of an audit. The statistical population of this research was the executive directors of small and medium companies, which was estimated using the simple random sampling method and Cochran's formula at the statistical error level of 5%, the sample number of 350 executive manages of SME. The data collection tool is a questionnaire. Partial least squares structural equation modeling was used to test the hypotheses of this research. The study of 350 executive manages of SME showed that the connecting communication style and providing information have a positive relationship with rapport between the financial auditor and the client and that rapport, in turn, has a strong relationship with the client's perceptions of the technical quality of the audit. In addition, connecting communication style, providing information and social cognitive capital have a direct (positive) relationship with the agencies regarding the technical quality of the audit. This study contributes to the audit literature by clarifying the important role of communication effectiveness, rapport and social cognitive capital in the relationship between the auditor and the client.