The invention discloses a water pump testing device. The water pump testing device comprises a water storage tank, a hand valve, a flowmeter, a rigid straight pipe, a hose, an electromagnetic valve, adrain electromagnetic valve, a pressure transmitter, a telescopic sleeve, a piezometer tube, an electric regulation valve, a hydraulic lifting platform and a control cabinet. The water pump testing device is a closed testing device adopting the modular design and thus can be conveniently mounted on the field of a water pump assembly line, and water pump transportation is reduced. On the other hand, the hydraulic lifting platform is arranged on a water pump testing station so that water pumps can be conveniently adjusted when the central heights of inlets/outlets of the water pump are different; and the inlets and outlets of the water pumps and water pump connecting pipes are clamped through a hydraulic device, and automatic connection and pressing are achieved, so that the labor intensityof operators is relieved, and the water pump testing efficiency is improved.