Liu, YD (reprint author), Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China.
Electron Cloud Instability (ECI) may take place in positron storage ring when the machine is operated with multi-bunch positron beam. According to the actual shape of the vacuum chamber in the BEPC II, a program has been developed. With the code, we can calculate the electron density in the chamber with different length of antechamber and the different secondary, electron yield respectively. By the simulation, the possibility to put clearing electrodes in the chamber to reduce the electron density in the central region of the chamber is investigated. The simulation provides meaningful and important results for the BEPC II project and electron cloud instability research.