Abstract: Combined with value stream analysis and lean tools, the lean improvement of connector assembly process was studied in A workshop’s connector assembly process. In order to identify the non-value-added links in production, the current value stream mapping was drawn through field investigation firstly. Meanwhile, the causes of non value-added factors, including unreasonable logistics layout, backward production mode, low line balance rate, much WIP and low standardization level, were figured out by virtue of the lean thinking. Finally, with the help of various lean production tools and methods, it optimized workshop layout and logistics, designed pull production, implemented just-in-time distribution, improved line balance and implemented standard operation. It successfully reached that the per capita efficiency of the workshop was increased by 35.02%, the production cycle was shortened by 26.93%, and the WIP was reduced by 26.78%.