Abstract: The Bainaimiao gold deposit in Inner Mongolia occurs in the Cu-bearing greenstone series of Bainaimiao group. Three sets of shear joints with different directions are developed in the rock, i. e. the E-W-trending sectional conjugate shear joints, NE- and NW-trending conjugate shear joints, and NNE-trending sectional conjugate shear joints. There are also some tensional joints and partial joints. The origin and forming order of joints, as well as the relation between joints and the ore-controlling faults are recognized with the analysis on joint sets and the relation between joints and principal stresses.