Our study decomposes the wage gap by gender and employment type to analyze the characteristics of the Korean PhD labor market. Unobserved heterogeneity is controlled by employing a more homogeneous PhD holders sample compared to general workers, and analysis results in which selection bias is corrected are derived by combining PSM with various wage decomposition techniques. As a result of decomposing the gender gap among PhD holders using RIF decomposition, a distributional approach, a clear sticky floor and limited glass ceiling are empirically confirmed. And, the generalized wage decomposition employed to analyze the employment type wage gap indicates that there are serious discrimination against temporary contracts in the PhD labor market, but STEM field is found to be somewhat better than other averages. In order to resolve this wage disparity against minority groups in the highly educated labor market, it is necessary to establish legal and institutional foundation for improving working conditions, and introduce reasonable wage structure.