The wider band gap of ZnSn(OH)6 (ZHS) leads to higher resistance and low sensitivity to gases, and doping is one important way of reducing resistance and improving gas sensitivity. In this paper, cubic ZHS and Bi-doped ZHS were successfully prepared by hydrothermal method and analyzed by XRD, SEM, TEM and XPS, respectively. The results are as following: XRD pattern of the samples are consistent with ZHS standard card, and the XRD characteristic peak shifts to the left after Bi doping; the size of the cubic particle decreases greatly; Zn, Sn, O and Bi elements are evenly distributed. The replacement of Sn with Bi will form a displacement impurity, and insert a shallow donor impurity level at the bottom of the conduction band. As a result, the carrier concentration increases while the band gap width and material resistance decreases. Therefore, the performance of the sensor is greatly improved.