A novel continuous revolving electro-hydraulic servo cam-rotor vane motor was introduced with its operating principle. The analytic formulae of the motor’s instantaneous torque and speed were derived. The effect of cam-rotor transition curves on improving the motor’s performance and the design criterion were discussed from the aspects of motor’s torque and speed fluctuation, and the dynamic and forcing characteristics of transition curves. The theoretical inference and characteristic analysis of four transition curves were conducted including secondary uniform acceleration-deceleration curve, secondary sine curve, secondary cosine curve and secondary Archimedes curve. Experimental results proved that the secondary cosine curve was suitable for the transition curve of the cam-rotor vane motor, which was used in three-axis motion simulator, and was also in favor of improving the performance of the motor.