Bian, T.J. Cai, Y. Cui, X. Gao, J. Koratzinos, M. Sha, B. Su, F. Wang, D. Wang, Y. Xiao, M. Zhang, C. JACoW Geneva, Switzerland 978-3-95450-187-8 10.18429/JACoW-eeFACT2016-TUT2H3 English 79-84 TUT2H3 ion dynamic-aperture dipole sextupole wiggler Contribution to a conference proceedings 2017 2017-07 https://doi.org/10.18429/JACoW-eeFACT2016-TUT2H3 http://jacow.org/eefact2016/papers/tut2h3.pdf CEPC is next generation circular collider proposed by China. The design of the full energy booster ring of the CEPC is especially challenging. The ejected beam energy is 120GeV, but the injected beam only 6GeV. In a conventional approach, the low magnetic field of the main dipole magnets creates problems. we have two ways to solve this problem, Firstly, we propose to operate the booster ring as a large wiggler at low beam energy and as a normal ring at high energies to avoid the problem of very low dipole magnet fields. Secondly, we implement the orbit correction and correct the earth field to make booster work.