The Hefei Advanced Light Facility (HALF) is a soft X-ray and VUV diffraction-limited storage ring light source, and the construction of HALF has just been approved by the Chinese government. The electron beam energy of the HALF storage ring is 2.2 GeV; the circumference is 480 m; the natural beam emittance is 86 pm·rad; and there are 20 long and 20 short straight sections in total. This paper will report the physics design progress of the HALF storage ring, including lattice design and optimization, simulation and calculation of beam injection and collective effects.