The Shanghai Synchrotron Radiation Facility (SSRF) is an intermediate energy light source under design and R&D at Shanghai National Synchrotron Radiation Center (SSRC). It is based on a 3.5 GeV electron storage ring with a circumference of 396 m, a beam current of 200-300 mA and a beam emittance of 5-12 nm/spl middot/rad. Since its R&D began in 1999, the design of the SSRF has been evolved smoothly towards a cost-effective machine required by its future users, and the prototypes of its key components have been manufactured and tested up to the design specifications. This paper reviews the design and R&D progress of the SSRF project and presents its current status.