Analysis of the variations in the three-dimensional structural forms of the tungsten veins in the Xihuashantungsten district has proved that echelon structures of the veins were formed by the changes in stress directionthat caused the breakdown of the individual single veins. and are different from the echelon faults formed inshear zones. Echelon structures of the veins were produced near the lithologic boundary as a result of the rota-tion of stress direction in their neighbourhood and their control of vein distribution. The change in the echelonpattern caused by the varlation in the attitude of lithologic boundary surface in the district is an interestingstructural phenomenon, The echelon structures also reflect the variation characteristics of adjacent veins in theprocess of their propagation.