Workpiece fixing device of water jet cutting machine

The utility model discloses a workpiece fixing device of a water jet cutting machine, which relates to the technical field of fixing devices and comprises a groove body, a pipe with a valve is arranged on the lower portion of the groove body, platform plates are arranged at the upper end of the groove body in a bilateral symmetry mode, and base blocks are arranged at the upper ends of the platform plates in a front-back symmetry mode. A positive and negative screw rod is rotationally connected between the base blocks on the rear side, a polished rod is arranged between the base blocks on the front side, threaded cylinders are in threaded connection with the outer side of the positive and negative screw rod in a bilateral symmetry mode, cylinders sleeve the outer side of the polished rod in a bilateral symmetry mode, and clamping plates are arranged between the cylinders and the threaded cylinders which are opposite in a front-back mode; according to the utility model, material plates are received by the stora