Zhang, J.R. Chi, Y.L. Gao, J. Li, X.P. Meng, C. Pei, G. Pei, S. Wang, D. Yu, C.H. JACoW Publishing Geneva, Switzerland 978-3-95450-216-5 10.18429/JACoW-eeFACT2018-TUPAB04 English 139-142 TUPAB04 linac positron electron emittance damping Contribution to a conference proceedings 2019 2019-04 https://doi.org/10.18429/JACoW-eeFACT2018-TUPAB04 http://jacow.org/eefact2018/papers/tupab04.pdf The CEPC injector consists of linac and booster. To meet the requirement of the booster, the linac should provide 10 GeV electron and positron beam at a repetition frequency of 100 Hz. In this paper, the overall design of the linac has introduced. For the linac one-bunch-per-pulse is adopted and bunch charge should be larger than 3 nC in the design. A 1.1 GeV damping ring with 75.4 m circumference has adopted to reduce the transverse emittance of positron beam to suitably small value.