The invention relates to a tobacco seedling grafting clamp, which is rectangular overall and consists of a scion clamping mechanism and a stock clamping mechanism connected up to down vertically, wherein the bottom surface of the scion clamping mechanism and the top surface of the stock clamping mechanism are both bevels and in parallel each other; each clamping mechanism consists of a first clampblock and a second clamp block in abutting joint, the first clamp block and the second clamp block are arranged at equal altitude and each clamp comprises a clamping steel channel; edges of the two clamping steel channels of each clamping mechanism are in abutting joint, and magnetic layers in mutual attraction are arranged on the abutting joint end faces of the steel channels of the scion clamping mechanism and the stock clamping mechanism. According to characters of tobacco seedlings, the tobacco seedling grafting clamp can realize quick cutting of scions and stocks of tobacco seedlings andaligned grafting of the scions and stocks, thereby promoting standardized work of preparation of stocks and scions and improving production efficiency of grafted seedlings.