A semi-analytical method was proposed to solve the mechanics problem of stamping a sheet on elastic die. The sheet was di-vided into four parts according to its deformation and contact with the punch and elastic die. Analytical solutions were derived individu-ally for each part by using elastic large deflection and plastic large deformation. Solutions were found out with MATLAB by developinga numerical algorithm. Interface forces were obtained by iteration under the compatibility conditions between the neighboring parts ofthe sheet. Computation shows the method is efficient.