Abstract: Under the condition of serial processing hardware in low-end microcomputers the speed of which is lower, the inference process can be sped up more than 10 times by means of the concept of “heuristic processing”, hierarchical search strategy and matching strategy, and setting the maximun search length presented in this paper. Furthermore, a serial problems of automatic english parsing have been solved and the size of knowledgebase has been reduced after intraducing semantic information, staged resolving syntax ambiguities, integrating Top-down and Bottom-up analysis, and transforming all Yes/No questions into corresponding declarative sentences.