The deformation principle and mathematical model of magnetic shape memory alloy (MSMA) were introduced.Aiming at improving the response speed of hydraulic components and the working performance of the hydraulic system,the applications of MSMA in the hydraulic fields such as hydraulic fluid control,hydraulic control valve and micro hydraulic pump was reviewed.For improving the responsiveness and work efficiency of the hydraulic system to a greater extent,the conceives of MSMA application in hydraulic components gap sealing,absorbing vibration and selfsensing effect were proposed.