The study of elastic parameters is an important means in subtle gas reservoir exploration. In the absence of multiwave and multicomponent seismic data, the adoption of rock physical modeling, the separation of P and Swave based on AVO data and the inversion of elastic parameters using P and Swave data constitute a practical and feasible method for predicating elastic parameters. This paper puts forward a new method based on μλ for predicting reservoir, which was used in gas well site allocation in the XC gas field, resulting in the successful  deployment of exploration wells. The results confirm the reliability of the method in predication of subtle gas reservoir. This method hence has a bright future in application.