This paper builds up a model to establish the causal link between labor market flexibility and export technological sophistication by introducing the theory of enterprise heterogeneity,using binary marginal analysis into trade expansion. We use the method of Hausmann et al. (2007) to calculates the export technological sophistication of 22 manufacturing industries in China during 2000-2010,and on this basis, empirically test its determinants. Study finds that,the increase of labor market flexibility leads the upgrade of export technological sophistication,mainly through the effect of human capital. In addition, based on the industry heterogeneity,labor market flexibility play some positive role in technology intensive industries but not in capital and labor intensive industries; While the effect of industrial output volatility is negative.