Abstract: Hydrodynamic cavitation is regarded as a green, efficient, and eco-friendly water disinfection technology that produces no by-products. In this paper, three kinds of blade-shaped rotors with different suction surface radians are proposed. Through numerical simulations, we compared and analyzed parameters like cavitation rate, gas phase, pressure, and flow velocity. The effects of suction surface radian and rotational speed on cavitation characteristics of rotor-radial groove hydrodynamic cavitation reactor were studied. The results show that when the rotational speed is 5040 rpm, the cavitation volume and cavitation rate in the rotor region with 60 degrees suction surface radian are the largest, showing the optimal cavitation performance. Under this working condition, the rotor low-pressure zone is the largest, and the dynamic balance of cavitation development is achieved by optimizing the pressure gradient distribution. The fluid velocity near the suction surface of the blade is significantly higher than that of other blade shapes, which strengthens the effect of cavitation. When the suction surface has the same radian, increasing the rotational speed leads to an increase in flow velocity, a decrease in the internal pressure of the reactor, and the subsequent emergence of a low-pressure zone. This expansion of the gasification region can significantly enhance the cavitation effect of the reactor.