The vacuum system of the Synchrotron Radiation Research Center 1.3 GeV electron storage ring was designed as a low contamination ultrahigh vacuum system In addition to the standard treatments for the ultrahigh vacuum components, several contamination reduction methods, such as oil-free machining processes, completely oil-free pumping systems, and dust-controlled installation processes, were adopted in the manufacturing processes. The benefits of the low-contamination treatments were verified by the resultant fast-beam cleanup, low degree of dust trapping, and low partial pressures of the carbonaceous residual gases in the vacuum system.