Negative flow control hydraulic system of rotary drilling rig and rotary drilling rig

The utility model discloses a negative flow control hydraulic system of a rotary drilling rig and the rotary drilling rig comprising the same. The negative flow control hydraulic system of the rotary drilling rig comprises a negative flow control pump, a main valve and an executive component and also comprises a sequence valve and a shuttle valve, wherein the oil inlet of the sequence valve is mutually connected with the oil outlet of the negative flow control pump; a first oil inlet of the shuttle valve is mutually connected with the oil outlet of the sequence valve; a second oil inlet of the shuttle valve is mutually connected with a negative feedback port of the main valve; an oil outlet of the shuttle is mutually connected with a control port of the negative flow control pump; and the opening pressure of the sequence valve is not higher than the overflow pressure of the main valve. When the delivery pressure of the negative flow control pump is higher than the overflow pressure, the sequence valve is opened, and part of oil delivered from the negative flow control pump enters the control port of the negative flow control pump through the sequence valve and the shuttle valve in sequence, and thereby, the delivery rate of the negative flow control pump is reduced, the overflow loss is avoided, and an effect that the energy is saved is achieved. Moreover, the negative flow control hydraulic system of the rotary drilling rig is simple in structure and lower in equipment cost.