The new kind of roller pump is the combination of radial ball piston and vane pump. Based on the characteristics analysis of elliptical area and length, the volume formula of double-acting elliptical orbit roller pump was deduced, and the flowing and pulsating of the pump were obtained. At last through the simulation , the effect of the structural dimensions on the flowing and pulsating of the pump was received. The analysis results indicated that the flowing of the pump is the five times of that of radial piston pump, and the 1.5 times of vane pump at the same structural dimensions. And the pulsation rate was slightly increased. There was a phase difference comparing with radial piston pump and vane pump, which was 13° in the article. The pulsation was generally reduced with the increasing of rollers’ number, but it was larger with the number being a multiple of 4. The output characteristics of the analysis results provided a theoretical basis for the roller pump structure optimization and noise and vibration reduction.