Aiming at the insufficiency of hydraulic fault diagnosis method for bridge inspection vehicle and the need of fault maintenance, an active hydraulic test method for bridge inspection vehicle fault was proposed. The composition branches of the bridge inspection vehicle and the existing fault phenomenon were described. The theory of hydraulic active test for hydraulic system leaking state of bridge inspection vehicle was studied. Based on the theoretical research results, the leakage state of the hydraulic system of a bridge inspection vehicle was tested. The test results verify the feasibility of the hydraulic active test method for bridge inspection vehicle.