The production method of austenitic stainless steel plate fin heat exchanger includes the following steps: part preparation: partition, sealing strip, fin, sealing head and connecting pipe preparation; cleaning before welding; acid pickling to remove oil, dirt and oxide, and using high-pressure water to wash; element assembling and holding; vacuum braze welding, adopting argon arc welding to weldscaling head and connecting pipe, making general assembly; test and inspection, making x-ray inspection, helium leak detection, flow resistance test, pressure test, TUV, ASME and other test and inspection. Said invented process raise the production quality of said stainless steel plate fin heat exchanger, tensile-strength of connector and its service life.