Dongzhongla ore deposit is located in the Zhaxue-Yaguila mineralization area, Nyainqentanglha Range, Tibet and is a new founded middle-large size lead-zinc deposit. The host quartz veins in the Dongzhong lead-zinc deposit was measured by laser microprobe 40Ar-39Ar dating method in order to obtain the ore-forming age. As a result, the isochron age of the ore is (42.2±1.7) Ma, inverse isochron age is (42±3) Ma with the MSWD value of 2.4, and the initial 40Ar/36Ar value of 303.6±1.4. The measured age is in agreement with the inverse isochron age within a reasonable error range, and the dating results can be regarded as the ore-forming age of the Dongzhong lead-zinc deposit (formed during Early Eocene).