The responses of a long span concrete filled steel tubular (CFST) arch bridge subjected to spatially correlated ground motion are analyzed. By using the stochastic vibration method, the time history of ground motion on the bridge site is simulated. The influences of spatial variation of the ground motion, such as uniform excitation, wave passage effect and partial correlation effect on seismic responses are studied based on the dynamic equilibrium equation for multi-support excitations. The calculated results show that the wave propagation influences the internal forces of the arch significantly. The effect of partial coherency is more complex compared to that of the wave propagation, yet it can be neither neglected. For long-span CFST arch bridges, it is critical to consider the effects of the spatial variation of ground motion.