Finite element method was used in the present study, of stress distribution of supporting tissuesunderlying extension edentulism which were restored with RPD using telescopic crown. mesial anddistal occlusal rest respectively as retainers were tested by means of finite element. Results showedthat the stress of both abutment and underlying supporting tissues of telescopic crown retaineddemure were more evenly distributed than that of the other two types, and it produces no trauma tooral hard and soft tissues, thus proved to be a sound way of restoring extension edentulism.