Aiming at unbalanced radial force of hydraulic motor, the concept of couple hydraulic motor was proposed, which drove the rotor by a couple acting on the rotor, so that the rotor of the motor was subjected to the balanced radial pressure, the force condition of the rotating parts of the blade motor was improved and the service life of the motor was improved. The principle of three type’s couple hydraulic motor under different forms of action was elaborated. Based on the rotor radial force as the starting point, the relationship between number of blades and couple was analyzed in detail. Then it was got that even-acting hydraulic motor with even leaves and oddacting hydraulic motor with number of blades can be divisible by the motor actions can only be called the couple hydraulic motor. Finally, the radial force of the rotor was analyzed with the doublestator couple motor as an example. The mathematical model of the rotor radial force of the double-stator hydraulic motor in four different working modes was established, and the characteristics of the rotor radial force of the motor under four different working modes were analyzed. And the experimental platform was set up. The results showed that in four different working modes, the radial force acting on the rotor and the position of the action were periodically changed, and the radial force of the rotor was the smallest when the internal and external motor was differentially working. When the inner motor and the outer motor worked separately, the radial force was the second, and the radial force was the largest when the inner and outer motors worked together. Through the experiment of the prototype, the correctness of the principle of double-stator couple hydraulic motor and the rationality of the design of motor structure were verified, which laid a foundation for the future research and development of the double-stator couple hydraulic motor.