In order to solve the problem of large leakage in traditional labyrinth seal, a new type of labyrinth seal structure with cascade for reference to cascade blowing effect is proposed in this paper. The working principle of the new sealing structure was analyzed, and a numerical solution model for three-dimensional traditional sealing and new sealing was established. On the basis of verifying the accuracy of the solution model, the effects of rotor rotation direction, rotational speed and pressure ratio on the leakage rate of the traditional and new labyrinth seals are studied, and the flow field characteristics and leakage characteristics of the traditional and new labyrinth seals are analyzed. The sealing mechanism of the new seal is revealed. The results show that the leakage of the traditional labyrinth seal remains the same when the direction of rotation of the rotor is different, and the leakage of the new labyrinth seal decreases by 6% when the rotor rotates in the forward direction, and the rotor reverses its phase. Compared with the rotor does not increase by 6%; at speeds below 5000r/min, with the increase of the rotor speed, the leakage of the traditional labyrinth seal almost unchanged, while the leakage of the new labyrinth seal decreased by 10% to 15% When the rotation speed is higher than 5000r/min, the leakage of the traditional labyrinth seal decreases by 2% to 5% with the increase of the rotor speed, and the leak rate of the new labyrinth seal decreases by 15% to 25%; Increased, the leakage of the traditional labyrinth seal and the new labyrinth seal increased, but the leakage of the new labyrinth seal decreased by more than 15% compared to the traditional labyrinth seal; Compared with the traditional labyrinth seal, the new labyrinth seal has a high and low pressure region on the cascade when the rotor rotates because the rotor contains a cascade, creating an air flow that is in the opposite direction to the leaking gas, plays a role in increasing resistance to suppress leaks. In this paper, a new labyrinth seal structure of rotor with cascade is presented. The sealing characteristic of the new seal structure is better than that of traditional labyrinth seal.