Continuous sheet metal forming (CSMF) is a novel technology for manufacturing doubly curved sheet metal parts. In this process, an upper flexible roll and two lower flexible rolls are employed as a forming tool, with the rotation of flexible rolls, the sheet metal is bent in the longitudinal and transverse directions simultaneously. In this study, the basic principle of CSMF system is introduced and the basic mathematical model to control the CSMF process is presented. Based on the analysis of the sheet metal deformation in longitudinal direction, the formulations to determine the finial curvature of the deformed sheet metal and to estimate the downward displacement of upper roll are obtained. Forming experiments for torus-shaped surface and saddle-shaped surface were carried out. The dimensional accuracy and smoothness of the CSMF parts were measured and analyzed. The experiment results confirm the validity of the presented mathematical models and shows that CSMF can be effectively used in forming of doubly curved surface parts.