The invention discloses a local reverse circulation coring drilling tool test system for loose and broken formation. The system comprises a drilling tool, an outer tube of which is detached, a driving device, a rotation speed measurement device, a negative pressure display device and a backwater collection device. The drilling tool comprises a connector, a negative absorption element, a transition element, a transition communication element, an inner tube connector, an inner tube, a spring card and the outer tube. The driving device is connected to the negative absorption element of the drilling tool through an extension shaft. The rotation speed measurement device comprises a light reflector and a photoelectric rotation speed meter, wherein the light reflector is attached to the extension shaft, and the photoelectric rotation speed meter is arranged right opposite to the light reflector. The negative pressure display device is connected with the inner pipe of the drilling tool. The backwater collection device is connected with a water outlet of the negative pressure display device of the drilling tool. According to the test system, relation among pump volume, pump pressure and rotation speed of an impeller and shafts in the drilling tool is tested conveniently, and relation among rotation speed of the shafts and a meshing gear, negative pressure and backwater efficiency is tested; and the system can provide basis for design and selection of structure parameters, installation parameters and working parameters of the local reverse circulation coring drilling tool for loose and broken formation.