The invention discloses a crystal welding device, and relates to the field of crystals.. The crystal welding device comprises a rack, a laser generator and a crystal clamping mechanism; the crystal clamping mechanism comprises a rotating motor, a crystal positioning block and a membrane clamping mechanism, the membrane clamping mechanism comprises a sliding table and a membrane positioning block,the sliding table can slide in the left and right direction, the membrane positioning block is arranged on the left side of the sliding table, an electric control system is further included and is electrically connected with the laser generator and the rotating motor, two parts are tightly pressed, through the laser heating melting welding manner, the two parts can be evenly and compactly connected, and the welding quality is higher; in addition, through a fixing table, a pull rod and a spring, the membrane clamping mechanism and the crystal clamping mechanism can be conveniently kept in tightpressing or separation, and through an absorbing device, the membrane is prevented from falling off when the sliding table moves.