The invention discloses a hydraulic device leakage measuring device, which comprises an oil tank, a first hydraulic pump, a second hydraulic pump, a first three-way valve, a first two-way valve, a second two-way valve, a flow rate sensor and a second three-way valve, wherein the second three-way valve is used for connecting a hydraulic device, the two ends of the first three-way valve are inlets, another end is an outlet, the inlets at the two ends are either-or paths, one end of the second three-way valve is an inlet, the other ends are outlets, the outlets at the two ends are either-or paths, the oil tank is respectively connected with the two inlets of the first three-way valve through the first hydraulic pump and the second hydraulic pump via pipelines, the outlet of the first three-way valve is respectively connected with one end of the first two-way valve and the second two-way valve through pipelines after the flow division, the other end of the first two-way valve is connected with the flow rate sensor, is then communicated with the other end of the second two-way valve, and is connected with one inlet of the second three-way valve, and the two outlets of the second three-way valve are respectively connected with the hydraulic device and the oil tank.