This mixed-method study explored the influencing process of professional learning communities (PLCs) on teacher job satisfaction in China. A questionnaire survey on 488 teachers in 16 primary schools in Shanghai was administered to examine the effect of PLCs on teacher job satisfaction. Follow-up qualitative interviews on ten teachers were conducted to explain how such effect took place. Results show that the organizational characteristics of PLCs which comprise supportive leadership, organizational structure and cultural barriers, had significant and positive effects on the individual characteristics of PLCs, i.e., collaborative inquiry and sharing and shared purpose and responsibility, which further significantly and positively predicted teacher job satisfaction.