In existing theories and methods for qualitative reasoning，there are some deficiencies of the capability of describing the real world．This paper developed K．Forbus’QPT(qualitative process theory)and proposed an extended way QuIOS tO describe Quali-tative reasoning．In this approach，the quantity types of QPT are generalized widely and the mechanism of expressing open physical systems is shown with the aid of processes restricted and guided by events．Besides，after having introduced the new concept of Quantity Views，this paper presented two sorts of inheritance mechanism about quantities in QUIOS and have shown that they will not raise any contradiction under given condi- tionS．