The Euler-Bernoulli beam theory is used to establish the vibration differential equation of the rigid catenary, the cantilever support device is equivalent to the spring, and the pantograph is equivalent to the three mass block model. The double-pantograph-catenary (DPC) dynamic coupling model is established by using the penalty function, and utilize Newmark- $\beta $ solved the model, verifying the reliability of the model with the field test contact forces of the rigid catenary system (RCS) of Xi’an Metro in China, and illustrating the vibration characteristics and fluctuation propagation characteristics of the rigid catenary structure in combination with the fluctuation propagation theory of beam and the sag model of rigid catenary. Based on the model, the dynamic interaction mechanism between the pantograph and the rigid catenary is studied, including the influence of different spans, speeds on the dynamic contact force of the DPC, the flow field of the pantograph is analyzed with ANSYS, and the influence of train induced wind in the tunnel is studied in combination with the DPC model. The results show that when the train operates on RCS with a double pantograph, the contact force fluctuation of the trailing pantograph (TP) is more severe than that of the leading pantograph (LP); Among the three common spans of 6m, 8m, and 10m, when the speed is less than 80 km/h, the span of 8m or 10m should be selected, when the speed is 80–140 km/h, the span of 6m or 8m should be selected, when the speed is greater than 140 km/h, the span should be the minimum 6m; With the increase of the wind velocity and the angle of attack, the fluctuation of the pantograph-catenary contact force of the RCS increases, and compared to the LP, the contact force fluctuation of the TP is greater.