The article A discussion on Unable to Mix up the Limitation of Cognate Words and Interchangeable Words Journal of Baicheng Normal college(No.1,2005) advocates that it is unable to mix up the limitation of cognate Words and interchangeable words,starting with the mixture of the two concepts of interchangeable words and cognate Words in the two articles in Chinese Construction.However,according to the language material,we find the crossing of interchangeable words and cognates words.Simultaneously,we put forward the different views that how to judge cognate words and some illustration of ancient and modern words.