The installation of the vacuum system of the Synchrotron Radiation Research Center 1.3 GeV electron storage ring was completed in January 1993. Both the straight (S-) chambers and bending (B-) chambers are made of aluminum alloy. Oil-less machining processes were adopted in the fabrication of the B-chambers and some components of the S-chambers. Stringent welding processes were performed in a clean room in order to get a good welding quality and a clean chamber surface. The pumping system is a combination of several kinds of oil-free pumps. In the commissioning phase, the photon induced desorption phenomenon was clearly observed. The major desorbed gases are H-2, CH4, CO, and CO2. The desorption yields of these gases are described in this paper. An interlock system for the purpose of vacuum safety is also built in the system in order to increase the reliability of the vacuum operation. In the early stage of the commissioning, the malfunction of some ion gauges and quadrupole mass spectrometers were observed due to the beam interference. A solution has been found to reduce the interference.