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.