Lean production is for process improvement. It helps enterprises improve production and/or management processes, increase product quality, productivity and enhance enterprises' competitive advantages. Lean production has entirely different management thinking from other traditional production methods. This study explores lean production activity management and integrates value stream mapping into a lean process implementation framework which includes six improvement phases: pre-implementation campaign, definition of value, affirming value stream mapping, smoothing the flow, pull process and completion, and with total of 19 guiding steps. An empirical study of an auto air-conditioning (A/C) supplier implementing the framework is performed and the results are significant.