Abstract: A hydraulic transmission CAD system that was developed under the environment of AutoCAD was discussed.It put forward a new concept of design on hydraulic transmission technology,and makes the modernized,high-efficient and high quality design of hydraulic transmission possible.The application of hydraulic transmission CAD system to textile machinery design includes hydrostatics calculation,hydrokinetics calculation,hydraulic component calculation,hydraulic component query,hydraulic system drawing etc.It raised the design quality and efficiency of the hydraulic design for textile machinery and brings great convenience and economic benefits for textile machinery enterprises.