A metal mesh mechanical property testing device comprises a stand. A fixed mount and a box used for placing stones are arranged on the stand. The top and bottom of the box are both openmouthed. A hydraulic cylinder positioned right above the center of the box is arranged on the fixed mount. A power drive end of the hydraulic cylinder is connected with a pressing plate. A metal mesh is arranged between the box and the stand. A measuring point position on the metal mesh is connected with a lifting rope, the lower end of which is connected with a laser lamp shining downwards. The hydraulic cylinder is connected with an oil pump through a high-pressure oil pipe. The oil pump is provided with a dynamometer used for measuring oil pressure at real time. The testing device provided by the invention has scientific principle and simple structure. During the process of pressurizing the metal mesh step by step, the size of the box can be changed by connecting a connection board with different installation regulation holes. Different specifications can be measured, and deformation and stress rules of the metal mesh at different intervals of row spacing and column spacing can be obtained so as to provide certain basis for determining the row spacing and column spacing of bolt-mesh supporting anchor bolt in roadways and parameters of the metal mesh.