Micro-system technology is an advanced comprehensive technology which is supported by micro-nano theory and based on micro-integration method. Through the integration of functional modules, the micro-system technology can achieve single or multi-purpose micro systems. The application of the technology is of great significance to accelerate the overall improvement of the electro-optical system performance and meanwhile reduce the cost effectively. Based on the key technology progress in the field of micro-system in 2019, the current difficult problems are discussed, which provides references for researchers in this field.