The invention discloses a spark plug with a convex type ground electrode. The spark plug comprises a mounting rack, the grounding electrode and a central electrode, a work cavity is arranged in the mounting rack, the lower ends of left and right inner walls of the work cavity are provided with first and second material ports respectively, a workbench is fixedly mounted in the bottom wall of the work cavity, the upper end surface of the workbench is provided with a groove through which the ground electrode can be placed smoothly, a handling frame is fixedly arranged in the left side of the upper wall of the work cavity, a first cavity is arranged in the handling frame, a threaded rotating rod is rotatably arranged between upper end lower end walls of the first cavity, and in power connection with a first motor arranged in the top wall of the first cavity, a sliding block is arranged in the first cavity, and provided with a first threaded groove cooperated with the threaded rotating rod,the right side of the first cavity is provided with a chute communicated to the outside, and a clamping arm extending out of the lower end surface of the handling frame is installed in the chute in asliding way.