Technical problems existing in molding process of U-shaped sandwich structure composite skin was studied. Many aspects of molding process were ameliorated, which included honeycomb core stabilization process, honeycomb core shape control, cross interval grasped layer and shape detection of parts. The results showed that stabilization process for honeycomb core could make greatly improve the quality of honeycomb core chamfer of manual cut. The optimal design of shape models could great assistance in shape control of honeycomb core. The cross interval grasped layer could avoid pressure conduction problems existing in molding process, and effectively solve the problems of honeycomb shrinkage, layer folds and internal delamination. The association, which included simple snap-gauge, U-shaped clamping devices and feelers, realized the efficient measurement of the shape of the parts.