The invention relates to the field of welding, and provides a high-speed welding method of a thin metal sheet. The method comprises the steps of S1, dividing a welding track into a plurality of secondary welding sections; S2, arranging a plurality of welding points in each secondary welding section in advance; and sequentially marking the plurality of welding points; and S3, welding the first welding point in each welding section; then welding the second welding point in each welding section; sequentially welding in the same way until the N welding point in each secondary welding section is welded, and thus finishing sequential connection of the plurality of secondary welding sections and obtaining a complete welding line. According to the method, the thin metal plate can be fixed andprevented from welding deformation through the plurality of welding track sections; the alternative welding manner is performed, so that the heat dissipating time of the welding points can be increased, and the accumulated heat is decreased, and as a result, the weld penetration caused by thermal deformation and heat accumulation can be prevented; and meanwhile, low secondary section welding speedrealizes high overall welding speed.