This paper focuses on the numerical study of the melting process of the wax when using the “stuffy pipeline” operation to remove the wax. Transient two dimensional heat transfer analysis was performed by using the enthalpy-porosity and Volume of Fluid (VOF) methods in ANSYS FLUENT. This study aimed at revealing the phase change heat transfer characteristics of wax melting process. The effects of water temperature, the thickness of the wax layer and wax layer composition on the melting process were investigated. The results show that when the “stuffy pipeline” operation is adopted, the operation time should be controlled wisely, the effect of wax removal does not increase over time. Moreover, the thickness of the wax layer is smaller, and the effect of wax removal is greatly reduced. The composition of wax layer has a significant influence on the melting process. When the wax is distributed in a single or double layer, the liquid contours of wax varies greatly.