When a pocket with a small upper mouth and a large lower bottom is sewn, the pocket deforms when a template is pulled out, and the overall template already can not meet requirements of every users. Inorder to solve the problem, the invention discloses a composite template composed of a basic template body, a left telescopic side, a right telescopic side, a cover plate and a bearing, the left telescopic side and the right telescopic side are installed in guide grooves of the left side and the right side of the basic template. A left tailed telescopic cylinder and a right tailed telescopic cylinder drive a left big connecting rod and a right small connecting rod to drive the left telescopic side and the right telescopic side to extend outwards or contract inwards. When the pocket with the small upper mouth and the big lower bottom is sewn, the left telescopic side and the right telescopic side extend outwards, edge folding and shaping are conducted on the pocket, the shape of the telescopic sides is designed according to the shape of the pocket, after shaping is completed, the telescopic sides contract inwards, then the template is pulled out, the pocket does not deform, the sewingof pockets of various shapes can be realized, and the requirements of every users are met.