Multi-stage throttling labyrinth pressure reducing valve

The invention provides a multi-stage throttling labyrinth pressure reducing valve which comprises a spring cover, a shell and a lower end cover. An adjusting nut is arranged at the upper end of the spring cover, an adjusting spring is arranged between the adjusting nut and a valve element, a return spring is arranged between the valve element and the lower end cover, the valve element is located in a sliding sleeve, the sliding sleeve is fixed in the shell, the shell forms a high-pressure cavity of an inlet and an outlet, a transition cavity is formed in the valve element, the shell and the sliding sleeve form a low-pressure cavity I, the lower end cover and the valve element form a low-pressure cavity II, the sliding sleeve and the valve element are correspondingly provided with upper throttling ports which communicate with the low-pressure cavity I and the transition cavity, the sliding sleeve and the valve element are correspondingly provided with middle throttling ports which communicate with the high-pre