The concept of the couple hydraulic motor is put forward, which is different from the traditional hydraulic motor. Based on the principle of the multi-acting double-stators couple hydraulic motor, the theoretical torque is studied. Through analyzing the pulsating characterize and the influencing factors of the motor, the relationship between the pulsation and the numbers of sliders is obtained. When the number of the rollers and connecting rods equals to 8 or less, the torque pulsation of the hydraulic motor consisted of the even number of the rollers and connecting rods is lower than what number is odd. When the number of the rollers and connecting rods equals to 9 or more, the torque pulsation of the hydraulic motor consisted of the odd number of the rollers and connecting rods is lower than what number is even. Finally, a theoretical basis is provided for the design and experiment of the hydraulic motor.