The invention discloses a modeling method of an optimal power flow model of a receiving end power grid security domain. The method includes a first step: constructing a system security domain through analysis of stability of a power flow equation, namely stability of quiescent voltage, phase angles and oscillation frequency of a system, and N-1 operation standards, wherein N loads of the system can be converted into M different sets composed in the load direction according to given power generation dispatching standards to generate a critical load matrix for approximate treatment of the security domain; a second step: constructing a dynamic security constraint optimal power flow model; a third step: constructing a self-adaptive neural fuzzy inference system; and a fourth step: training the self-adaptive fuzzy inference system and constructing the optimal power flow model. The optimal power flow model well expounds the operation standards of current electric power system dispatching. The optimal power flow security domain approximation technology based on the self-adaptive fuzzy inference system can be applied to dispatching optimization between receiving end power grid areas after distribution of hierarchy and areas.