The SHG effects of substituted 3-thienyl chalcone compounds weremeasured. The relationship between structure and effect of substituted 3-thienyl chal-cone derivatives and substituted 2-thienyl chalcone derivatives were discussed. It isshown that their properties of high SHG efficient are similar to each other and the sub-stituted 3-thienyl chalcone molecules are easier to form non-centrosymmetric crystalstructure than substituted 2-thienyl chalcone molecules.