Abstract: The deficiency of traditional QSIM ( qualitative simulation for imp rise model) algorithm was ana2 lyzed. Using unconfirmed rational number to imp rove the descrip tion capacity of QSIM, and using group modeling method to model the uncertain relationship under the GDSS circumstance, the QSIM with character of physics logical reasoning and experts’experience reasoning with character of jump ing thinking are combined together, which not only made the QSIM algorithm be capable to make a innovational decision, but also made the incomp lete quality of traditional QSIM algorithm be partly solved.