To solve the problem of extension state recognition, an extension pattern distinguishing model was proposed. First, an extension pattern distinguishing definition was built; second, the characteristics of both static state and dynamic state were analyzed for universe of discourse; furthermore, a general framework of extension pattern discrimination was designed, and the formulas to calculate the degree of quantitative change and qualitative change were given in the paper; finally, both general and extension states of a given case were distinguished by using the proposed method. The experimental results demonstrate the feasibility of the proposed model for expression, analysis and discrimination of extension state. The extension pattern distinguishing model can effectively solve the pattern recognition problem of extension and states transformation which is inextricable for traditional extension pattern classifiers.