Presentor: Dr. Jingru Zhang (IHEP/Beijing) Title: Overall Design of the CEPC Injector Linac The CEPC (Circular Electron Positron collider) is 120 GeV electron positron collider. The 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 of 100 Hz, one-bunch-per-pulse is adopted and bunch charge should be larger than 3 nC. A 1.1 GeV damping ring with 75.4 m circumference has adopted to reduce the emittance of positron. For the accelerating structure and positron source are key technology, S-band structure and flux concentrator are developing now.