Abstract: The capital entrepreneur theory,which was originated by Zhang Wei-ying,interpreted successfully the phenomenon that the rich have precedence to become entrepreneur.However,such theory overlooked the fund-raising capability of the enterpriser.The matrix of critical capital,which is based on two hypotheses: free employment as well as unknowable perfect market and business skill,binds together Zhang Wei-ying's fortune choice and Knight's risk choice.This matrix holds that a person's risk orientation and critical capital is the significant foundation of his becoming an enterpriser.When the start-up capital is less than critical capital,he chooses to be an enterpriser;the more critical capital he owns,the greater desire he would have to be an enterpriser.When the coefficient of risk orientation is more than that of critical risk orientation,he chooses to be an enterpriser;the higher the coefficient is,the more he expects to be an enterpriser.