Interesting results from BEPC/BES answer many interesting questions, and also indicate there are more important physics to be studied in the tau-charm energy region. 

    IHEP Beijing is going to make a major upgrade  of BEPC, so called BEPC II, to increase the luminosity of the machine by two magnitudes, and to improve the performance of BES significantly. An additional storage ring will be built inside the existing storage ring at the BEPC tunnel with a large angle crossing of 11 mrad. The design luminosity is 10^33 cm-2 s-1 at 3.1 GeV. 

    BEPCII aims at the precision measurements at the tau-charm energy region, and to search for new physics  phenomena. Chinese Government agreed to support the project. The physics goals, the design of the machine and the detector are reported.