 In 657, when the general Su Dingfang attacked Western Turkic Khaganate's Shaboluo Khan Ashina Helu (), Xue submitted a suggestion that if the wife and children of the chief of one of Western Turkic Khaganate's constituent tribes, Nishu Tribe (), who did not particularly support Ashina Helu but was forced to comply after Ashina Helu took his wife and children hostage, were to be captured by Tang forces, that they be immediately released so that the chief of Nishu would submit to Tang.When Emperor Gaozong approved this suggestion, the chief of Nishu did, indeed, join Tang's army.Su was subsequently able to defeat and capture Ashina Helu.