Gas separation device of hydraulic oil pump and use method of gas separation device

The invention discloses a gas separation device of a hydraulic oil pump. The gas separation device comprises a gas collecting pipe, an oil level detector and a mounting plate, the gas collecting pipe is vertically arranged on the mounting plate, the lower end of the gas collecting pipe is communicated with a gas outlet of the hydraulic oil pump, an exhaust port is formed in the upper end of the gas collecting pipe and provided with an electromagnetic valve, and the oil level detector is arranged on the gas collecting pipe and used for detecting the oil level in the gas collecting pipe; the control assembly comprises a valve controller, a pressurizing normally-closed contact, a pressurizing normally-open contact, an oil level upper limit normally-open contact and an oil level lower limit normally-open contact. Gas in the hydraulic oil pump is led into the gas collecting pipe, gas is exhausted by controlling a switch of the electromagnetic valve at the exhaust port, each contact is adjusted by combining a detec