It has been nearly a decade since the social service contract-out policies first implemented by the Guangdong and Guangzhou Government in 2009. Based on analysis of social service contract-out policies，development of social organizations and the professionalization of social workers in the past decade in Guangzhou，the artical found that there are three stages of development of social service contract-out policies in Guangzhou，namely experiment，promotion，and adjustment. It is through these three stages the social service system in Guangzhou is developed，and increasing numbers of professional social workers are trained. However，in order to build a more systematic training system for social workers in Guangzhou，the continuing education system，the stability of social workers，salary system and service network needs further improvements.