The application of wet shotcreting machines in China and the problems occurring in the application of 2 popular wet shotcreting machines are presented. The emphasis is placed on the presentation of the technical and structural principles of PS4J wet shotcreting machine. Study is made on how to improve the service life of the compressing hoses. Methods to estimate the central bending radius of the compressing hoses are recommended. The method to improve the pulse of the compressing pump and the characteristics of PS4J wet shotcreting machine to match JD150 shotcrete mixing machine are introduced and the comprehensive performance of PS4J wet shotcreting machine is provided.