Based on questionnaire survey of human resources department administrative persons and department managers of 111 firms from Mainland China, This paper analyses the relationship among the human capital, human resources management practices and firm performance under the dynamic environment of economic transition and economic globalization. We use four indicators to measure firms’ human capital, namely the quality and quantity of human capital, fitness of human capital, complementarities of human capital and specificity of human capital, and make an empirical test on the hypothesis through hierarchical regression and crosslevel analysis. The result shows that the impact of human resource management practices on firm performance partly performs through the intermediary role of human capital, and dynamic environment weakens the direct effect of resources management practices on human capital, thus weakening the intermediary role of human capital, that is, compared with the stable environment, dynamic environment plays regulating role between human resource management practices and human capital.