In this paper, we discuss the genetic relationship of Sino-Tibetan languages, especially that between Sino-Tibetan and Kam-Tai languages. We first review the methodology of correlated and complete sound correspondence and that of rank analysis. By adopting the latter methodology, we then demonstrate rank analyses of domestic animals, tool materials, numerals, and core words, all of which serve as case studies on the relationships between Old Chinese and such languages as Kam-Tai, Written Tibetan, and Written Burmese. Based on the distributional differences of sound correspondences across ranked lexical items in the aforementioned semantic domains, we propose a genetic tree of Sino-Tibetan languages whereby Kam-Tai is not related to Sino-Tibetan.