An aluminum alloy vacuum chamber, 4 m in length, for an undulator was installed in the 1.3 GeV electron storage ring of the Synchrotron Radiation Research Center in the spring of 1996. The inner cross section of this vacuum chamber is an elliptical shape, 10 mm in height and 80 mm in width. A beam life time of 7 h at 200 mA beam current was quickly achieved after beam cleaning on the new chamber walls. The impact of this new vacuum chamber, before and after the installation, to the storage ring was compared. The injection rate was reduced. The stronger beam loss during the injection was measured. The effects of a small vertical aperture and the effective pumping to the electron beam lifetime are reported. The planning in upgrading the storage ring vacuum system is also described.