Abstract: The paper intends to find the way by which it can improve the voluntary retention of migrant workers, through the study on the relationship between internal marketing and intent to stay. Based on 701 valid questionnaires collected from migrant workers, and use SPSS 21 and LISREL 8.70 to count and analyze,the paper supports that internal marketing has a positive effect on intent to stay, with the partial mediating role of organizational identification. Person-organization fit moderates the relationship between internal marketing and intent to stay, and influences the employees' behavior whether to stay or to leave. The paper also discuss the theoretical contributions and practical values.