Hydraulic system and rotary drilling rig including the same

A hydraulic system for a rotary drilling rig includes a main hydraulic circuit, which includes a hydraulic pump (3), a hydraulic execution component (140) and a reversing valve (9) connected between the hydraulic pump (3) and the hydraulic execution component (140). A self-locking mechanism is placed between two hydraulic cavities of the hydraulic execution component (140). The hydraulic system further includes a follow-up control valve (10) and a follow-up control overflow valve (11). The follow-up control valve (10) is connected between the oil inlet of the follow-up control overflow valve (11) and the main hydraulic circuit. The overflow pressure of the follow-up control overflow valve (11) may reflect on the main hydraulic circuit when the oil inlet of the follow-up control overflow valve (11) communicates with the main hydraulic circuit, so that action speed of the hydraulic execution component (140) can be adjusted by influencing flow of the hydraulic oil supplied to the hydraulic execution component (140) by the main hydraulic circuit. The hydraulic execution component (140) keeps synchronous action with the load component, so as to realize follow-up of the hydraulic execution component (140) and the load component.