Abstract: Based on the principle of meta-synthesis,this paper proposed the characteristic tree analogy and relevant theories for the analysis of similarity and difference among complex giant systems,while the authors derived the charac- teristic tree model structure and algorithm of calculating the similarity index quantitatively. Hereby an analogy analysis system of human-computer interaction was established. The principle of characteristic tree analogy was applied to soft rock roadway support design,which effectively solved the problem that cannot analyze the comparability between differ- ent projects quantitatively. Taking the research of Liangjia coal mine soft rock roadway support decision system as an example,the decision support system of roadway support design was developed based on the principle of characteristic tree analogy and the analogical transfer was achieved by excavating and analyzing the existing roadway support cases. Engineering practice shows that the decision support system can effectively achieve the functions of analogical objects retrieval,analogy analysis and support design consultation,which verifies the applicability and reliability of the charac- teristic tree analogy for soft rock roadway support design.