Abstract: Wire bonding is widely used for MEMS sensors packaging,but the conventional IC wire bonder limited the flexibility of the MEMS for the batch machining character.A manual wire bonder is reconstructed and integrated with vision feedback system based on zoom microscope for automatic packaging of MEMS sensors.A new autofocusing method for zoom microscope is proposed based on the analysis of zoom microscope model for acquiring good image in different magnification.Taking advantage of the zoom function of microscope,objects can be identified and located roughly with low magnification,and the precise position of objects can be calculated accurately with high magnification image.At last,the productivity of the flexible wire bonder is validated through a wire bonding experiment for MEMS pressure sensors.