Bismuthoan galena is a variety of galena, resulting from the replacement of Bi for some Pb in galena. This mineral occurs in the No. 11 orebody of the Lamo skarn-type Zn−Cu deposit in the Dachang ore field, but only in the No. 11 orebody of the Lamo deposit is developed such bismuthoan galena. This is closely related to such a geochemical background that the No. 11 orebody contains high Bi and Bi-sulfosalt minerals are well developed there. Eight electron microprobe analyses of five samples give 60.17–70.20% Pb (66.94% on average), 10.00–16.26% Bi (12.47%), 4.83–8.97% Ag (6.39%) and 13.25–13.98% S (13.65%). Its molecular formula is Pb0.76, Bi0.14, Ag0.13)1.03S. No galena so high in Bi has been reported in the literature and this is the first report in China.