The invention discloses a laser-transmission welded connection method, which belongs to the technical field of laser transmission welding, and particularly relates to laser transmission welding between metals and polymers. The laser-transmission welded connection method comprises the following steps of: firstly, carrying out micro-ultrasonic electrolysis combined machining process on the to-be-welded surface of a metal material so as to form concave pits in the surface of the metal material; connecting a lower-layer light absorption material which is the metal the surface of which is subjected to the micro-ultrasonic electrolysis combined machining process, and an upper-layer light absorption material which is a polymer in an overlapping manner, clamping the two light absorption materials by a restraint layer, and applying a welding pressure to the light absorption materials; and carrying out laser transmission welding on the light absorption materials by a semiconductor laser so as to enable a surface temperature to fast reach a melting point of the upper-layer polymer and the surface of the polymer to be melted, thus forming an holding-on interface with a riveted structure at a weld joint and improving the connecting strength of laser-transmission welding since the concave pits are formed in the surface subjected to the micro-ultrasonic electrolysis combined machining process of the lower-layer metal, and the polymer with the melted surface layer flows into the concave pits under the action of the welding pressure.