There is inconsistency between the economy and reliability of power grid operation during power grid optimal dispatch and control decision-making. In order to co-ordinate the inconsistency, a risk decision model is constructed taking into account the real-time power grid operation. The model is based on the concept of risk. The goal is expectation maximization for load revenue. The amounts of decision making are the generating capacity and load cut. The constraints include state constraints before and after the incident or coupling between these incidents. The model combines power grid risk assessment theory with power grid decision theory, enriches and develops the power grid risk decision-making theory. Finally, a numeral case is proposed to prove the validity and feasibility of the model.