This paper presents a design of machine-readable Chinese thesaurus,the database of which fully expresses in a simple structure the all-dimensional cross-reference relations among the subject terms,making it possible for the document retrieval systems to do extension searching using narrower terms.This design is proven feasible in a simulated test on IBM 286 compatible computer.It also proposes a way to code the symbal lists,where by the whole codes are more directly perceivable with 50% of the storage space saved.