Abstract: Double-linkage zoom structure is composed of two groups connected together which is the zoom group for doing linear motion and the compensation group for doing non-linear motion. This structure has the characteristics of both the optical compensation and the mechanical compensation. This structure is easy to realize large zoom ratio, the system length is short and the cam curve is smooth. The radii and materials of components were established by using the PW method and the optical structure parameters relationships, and the initial structure meeting the design requirement was designed by CODEV software.