Abstract: Characteristics of cognitive psychology about entity similarity and formal features of Domain-specific question-answering systems are presented.Based on the structural-alignment and geometric similarity model,a new approach to Chinese word similarity computation is proposed.By separating the word concept description into two parts of attribute space and case space,which respectively process the structural alignment and calculate the distance of sememes aligned,the word concept similarity is made of the two parts distance with different weight.The method is applicable to compute the similarity of two sentences represented in semantic vector(quasi-case frame).The world ontology,domain ontology and domain knowledge text are fused to make up the knowledge base for semantic computation,and thus to drive a specific bank QA system.Experimental results showed that the method is capable of improving user satisfaction of QA systems.