An analytical electron positron circular collider optimized design method has been developed with carb-waist collision and CEPC parameters for Higgs, W and Z have been given by this method. For the lattice of CEPC collider ring, the combined magnet (dipole+sextupole)scheme has been developed to reduced the power consumption of the stand-alone sextupoles. The power consumption of the original sextupoles can be reduced by 75% even more. The design of the special twin aperture dipoles with sextupole component was given. Based on multi-sextupole optimization, the dynamic aperture for the combined magnet scheme is even better than the original lattice.