The invention relates to a tool clamp for mold cavity spray welding of a glass mold. The tool clamp comprises a rack, a mold horizontal clamping support driving mechanism, a mold horizontal clamping support and a reversing support driving mechanism; the rack is composed of a rack bottom plate, a rack left wallboard and a rack right wallboard, wherein the rack left wallboard is fixed to the left end of the rack bottom plate, the rack right wallboard is fixed to the right end of the rack bottom plate, and a rack cavity is formed in a space between the rack left wallboard and the rack right wallboard; the mold horizontal clamping support driving mechanism is supported between the rack left wallboard and the rack right wallboard; the mold horizontal clamping support is clamped to the mold horizontal clamping support driving mechanism at the position corresponding to the front side of the mold horizontal clamping support driving mechanism; and the reversing support driving mechanism is arranged on the side, back to the rack right wallboard, of the left wallboard and connected with the mold horizontal clamping support driving mechanism. The structure of the mold horizontal clamping support is simplified, and the size is decreased; clamping is convenient and saves labor, the strength of an operator is reduced, so that safety is improved, and accidents are avoided; the motion transmission link is omitted, and the energy-saving effect is shown; and the size is small, the center of gravity is reduced, the space is saved, and the stability and the motion reliability are guaranteed.