Virtual hydraulic circuits can be valuable complements to hydraulic circuit experiment education since that they can relieve the problem of lack of physical hydraulic experiment equipments. Flash is the most widely used software for creating plane animations for education. In this article, the process of constructing a virtual hydraulic circuit using Flash is demonstrated in detail by dividing the whole process into four steps: (1) designs the structure of the virtual hydraulic circuit, (2) creates virtual hydraulic component Flash symbols, (3) constructs the virtual hydraulic circuit Flash movie using the created virtual hydraulic component Flash symbols, and (4) synthesizes the mathematical models of the whole virtual hydraulic circuit, and implements numerical simulation algorithms using ActionScript language to drive the virtual hydraulic circuit according to the mathematical models.