[en] To enhance the performance of Hefei Light Source, which was designed and constructed two decades ago, an upgrade project would be carried out in the near future. The detail upgrade scheme was described in this paper. Firstly, the magnet lattice of storage ring should be reconstructed with 4 DBA cells, whose advantages are lower beam emittance and more straight section available for insertion devices. Secondly, the beam diagnostics, main power supply, transverse and longitudinal multi-bunch feedback, beam control and manipulation system would be upgrade to improve the beam orbit stability. Finally, the injection system of storage ring and injector, which is composed of electron linac and beam transfer line, would be updated in order to assure smooth beam accumulation process under new low emittance lattice. With above improvement, it is hopeful to increase the brilliance of Hefei Light Source by two orders approximately. After three-year upgrade project, the performance of HLS would meet the demands of advanced SR users.