With the enhanced competition of enterprises on the talent, the rational manpower planning in enterprises to protect the human resources needs of enterprises becomes an important driving force to promote the development of enterprises. Human resources forecast is the premise and basis of manpower planning, which is of great significance to the sustainable development of enterprises. This paper focuses on the human resource internal supply forecast and establishes the forecasting model based on Markov chain. Firstly, this paper analyzes the factors that affect the internal human resource supply and compare the methods of human resources internal supply forecast. Then, this paper provides the steps of the human resource internal supply forecast in enterprises, determines the construction method of the forecasting model, and establishes the Markov forecast model. Finally, this paper uses the proposed model to predict the human resources within the M enterprise and gives suggestions for the internal supply of the M enterprise which have certain practical significance.