The invention discloses a steel wire rope mesh tensioning device and a method. The steel wire rope mesh tensioning device comprises aluminum alloy joints, a fixing end, a tension sensor, a steel wire rope mesh, a tensioning end and a tensioning device. The tensioning device comprises a torque wrench, a draw bar and a locking nut, and the tension sensor and the torque wrench are respectively provided with corresponding display screens. The method comprises following steps: fixing one end of the steel wire rope mesh at the fixing end via one aluminum alloy joint at first, connecting the other end of the steel wire rope mesh with the tensioning end via the other aluminum alloy joint, and screwing down the locking nut so as to fix the steel wire rope mesh. The locking nut continues being screwed down by the torque wrench, corresponding torque values are displayed on the display screen of the torque wrench, simultaneously, by the aid of tensioning at the tensioning end, tension values of the steel wire rope mesh are displayed on the display screen of the tension sensor, quantization of force in a total tensioning process is realized, a reinforcing mode is improved, and standard quality is improved sufficiently.