Abstract: With the advancement of material science and manufacturing technology, hydraulic transmission technology (HTT), which has been widely applied in marine mechatronics, bionic robotics, aerospace, and petro-chemical equipment, tends to be miniaturization, light weight, high pressure, high power density, and environmental friendly. Combined with the application requirements, the features, performances and applications of micro-hydraulic components were presented and the trend of HTT was addressed in details. The paper provides a guidance for the development of micro HTT.