Bo th the variance of direct econom y effect and the variance of the t ran sm ission facto r of e2 conom y effect can cau se the variance of the gro ss indirect econom y effect of nat ional econom y. The fo rm er is called as ripp le effect; the lat ter is called as pertu rbat ion effect. The parper discu ssed and studied the two effect s. A cco rding to the data of the Sichuan p rovince inpu t2ou tpu t f rom 1987 to 1997, the ripp le effect s and pertu rbat ion effect s are studied. A t the sam e t im e, a new w ay called as locat ion chart by w h ich w e can catego ry the ripp le effect s of individual division s is pu t fo rw ard. A f ter studying, w e can cam e to a conclu sion: in the differen t phases of the ten years, the m ain facto rs that st im u lated the grow th of gro ss nat ional econom y effect are differen t. In the p rophase, them ain facto r is pertu rbat ion effect; in the m etaphase, is ripp le effect; in the anaphase, is the ou tcom e of the ripp le effect and pertu rbat ion effect.