The existing automatic clamping systems are mostly suitable for single machine manufacturing process,and it is difficult to meet the needs of multi-variety mixed production.There are some problems of different shapes and sizes of processing parts and low degree of automation,so the research on automatic clamping system for flexible machine processing line was carried out.The sub parent tooling fixture was used to solve the problem of parts difference,the automation level was improved based on the automatic tightening machine,and the automatic clamping system overall scheme was designed.The automatic clamping system of three-dimensional gantry movement platform and the design of the end executor were proposed based on the design of soft PLC,and the automatic tightening and servo control process were explained.Finally,the development and verification process of automatic clamping system were analyzed.Through the test and verification,the system has a high degree of flexibility,and the clamping process is unmanned.It can be quickly expanded with loading and unloading robots,AGV and so on,which has a certain engineering value.