This invention provides a process and device for simultaneous laser welding; after using the moving lower die and the fixing upper die to make the base and the lens attached, by using the light pipe, for example, transparent substances or other cheap materials, to make the laser, which is emitted from the laser source, emit through the lens to a welding region of the base after being processed, to operate rapid and average heating to the welding region; meanwhile, using the welding cylinder to press the base and the lens together, to make base and the lens pressed and welded together in molten state, and when welding, it does not generate powder or other defects, and, at the same time, it can make the height H and the width w of the generated waste selvage between [0, 0.4] mm, which can improve the performance of welding object more efficiently.