Abstract: To study the effect of hohlraum gas on both laser-plasma interaction and implosion symmetry, the paper presents the design, material selection and fabrication of gas bag target, the filling gas technology and the implementation of the target on the Shenguang Ⅱ facility. The gas bag target is made by gluing two 400 nm thick polyimide films to a 400 m thick aluminum (Al) washer. The target is inflated with gas through a small filling tube mounted into the aluminum washer and the polyimide is stretched to a near-spherical shape.