Pure Indium oxide powder was synthesized by chemical precipitation. In2O3 based gas sensing materials doped with noble metal catalyst were made by impregnation. The phase composition of powders was determined with XRD. The gas sensitivity of these side-heated gas sensors were tested in static state by using RQ-2 gas sensitive behaviour analyzer and ploted the curves of gas sensltivity against temperature for several kinds of gas. The results showed that In2O3 based gas sensors can be used to detect gas selectively or generally because of its high gas sensitivity, proper resistance and quick response and recovery.