By analyzing wear data of tungsten carbide coatings, a method of residual life prediction which combines wear monitoring data with historical data is proposed based on Gamma process. Firstly, prior values of Gamma process are confirmed on the basis of historical data. Secondly, prior parameters can be updated to posterior parameters with Bayesian method, and then the real-time reliability function of tungsten carbide coatings is established in order to predict the residual life. Finally, an example is used to validate the proposed method, and the results show that the proposed method satisfies the engineering requirement.