The invention discloses an internal-curve radial plunger hydraulic motor rotor assembly. The internal-curve radial plunger hydraulic motor rotor assembly comprises a rotor. The front side and the rearside of the rotor are provided with semicircular retaining rings. The semicircular retaining rings are connected with the rotor through sunk screws. The middle of the rotor is provided with pistons.The outer sides of the pistons are provided with bearing bushes. The outer sides of the bearing bushes are provided with cylindrical running pulleys. The cylindrical running pulleys are arranged at the outer end of the middle of the rotor. The outer sides of the cylindrical running pulleys are provided with a torque module. According to the internal-curve radial plunger hydraulic motor rotor assembly, when a hydraulic motor works, the pistons do planetary motion around the axis of the rotor while reciprocating in the axial direction of the piston, the semicircular retaining rings are fixedly connected with the rotor through the sunk screws, the sunk screws are mounted on the two sides of the circumference and the two sides of the axial direction of each piston, and meanwhile, due to the fact that the semicircular retaining rings are mounted from the two sides of the circumference, the internal-curve radial plunger hydraulic motor rotor assembly can be applied to a single-row rotor structure, a double-row rotor structure and a three-row rotor structure; and equipment is only provided with the semicircular retaining rings and the sunk screws, so that the universal and standardized level of product design is improved, and a product has good assembly technology property accordingly.