The invention provides a tool changing device for jujube tree grafting. The device comprises a cutter set, a cutter head, a cam mechanism and a power assembly, the cutter set comprises a scraper, a first breaking knife, a second breaking knife and a cut-off knife, the cutter head is of a ring structure, the cam mechanism is arranged in the center of the cutter head, and the cam mechanism and the cutter head are relatively independent. Four guide rail grooves are evenly formed in the cutter head, the scraper, the first breaking cutter, the second breaking cutter and the cut-off cutter are slidably installed in the guide rail grooves respectively, limiting pieces are arranged at the tails of all cutters in the cutter set, the cutter head is connected with the power assembly, and a steering engine drives the power assembly to move so as to drive the cutter head to rotate. When the cutter head rotates, the stationary cam mechanism ejects the cutters out, and the four cutters are cyclically reciprocated, so that the cutter replacement operation is convenient. The device is scientific and reasonable in structural design, safe and smooth in tool changing, diversified and complete in function, small in size, low in weight, convenient to carry and capable of effectively improving the working efficiency of jujube tree grafting.