In order to deeply understand the working characteristics of the swing system of concrete wet spraying machine, according to the structure and working principle of the swing system, the bond graph model and dynamic equation of the swing system were established by taking into account the motion response time of components such as the internal valve core of hydraulic element. The working characteristics of hydraulic components such as constant pressure pump, accumulator and electro-hydraulic directional valve were simulated and analyzed in the process of swing arm movement, and a swing arm swing test platform was built for experimental verification. The research results showed that the swash plate of constant pressure pump was in a maximum inclination angle state before swing arm movement reached a stable state. The high-pressure oil pumped out was used for the movement of left and right swing cylinders and the charging of the accumulator. The pressure of the accumulator gas chamber gradually increased with the increase of swing times of swing arm and finally stabilized at 14 MPa; after the swing arm movement reached a stable state, the inclination angle of the swash plate of the constant pressure pump changed periodically at 0°-19°, and the maximum instantaneous flow of the accumulator discharge reached 322.5 L/min, and the S-shaped distribution valve could realize the reversing within 0.24 s; the test results of the working pressure of the rodless cavity of swing cylinder were basically consistent with the simulation results, which verified the accuracy of the established model. The research results provide a reference for the further optimization of the swing system of wet shotcrete machine.