Hydraulic system and rotary drilling rig comprising same

The invention discloses a hydraulic system and a rotary drilling rig comprising the same. The disclosed hydraulic system comprises a main hydraulic circuit, wherein the main hydraulic circuit comprises a hydraulic pump, a hydraulic actuator and a reversing valve; the reversing valve is connected between the hydraulic pump and a pressure oil cylinder; and a self-locking mechanism is arranged between two hydraulic chambers of the hydraulic actuator. Compared with the prior art, the hydraulic system also comprises a follow-up control valve and a follow-up control overflow valve, wherein the follow-up control valve is connected between an oil inlet of the follow-up control overflow valve and the main hydraulic circuit. In the disclosed hydraulic system, when the oil inlet of the follow-up control overflow valve is communicated with the main hydraulic circuit, the overflow pressure of the follow-up control overflow valve can be reflected on the main hydraulic circuit; and the action speed of the hydraulic actuator is adjusted by influencing the flow quantity of hydraulic oil which is supplied to the hydraulic actuator by the main hydraulic circuit, so that the hydraulic actuator keeps synchronous action with a load part to realize the follow-up of the hydraulic actuator and the load part.