A laser and electric-resistance seam-welding synchronous composite welding method for an envelope-framework structure relates to a novel laser and electric-resistance seam-welding synchronous composite welding method, belongs to the welding field, and aims to solve the problems in welding the envelope-framework structure by the single laser, such as narrow seam, low shear strength of the seam, a plurality of air vents on the faying surface of the envelope and the framework. The invention aims at the workpiece with the envelope-framework structure to be welded, and adopts the laser and the electric-resistance seam-welding synchronous composite welding; the electric-resistance seam-welding adopts double-roller single-side welding, two roller electrodes are disposed on the front and the back sides of the upper top surface of the envelope along the seam formed by the contact of the envelope and the framework, so that the envelope is pressed to the lower framework in the travel forward, and the laser beam is always positioned in the middle position of the two roller electrodes during the welding process. The seam formed by the welding method can improve the shear strength more than twice in comparison with the base material, and the air vent amount per area can be reduced from about 10% to about 2% of the laser welding.