The invention relates to a method and system for monitoring characters of steam and water of a node in an electric power simulation system. The method comprises the steps of obtaining operation parameters of the node in the electric power simulation system; solving a heat and mass transfer simulation model of the preset node according to the operation parameters to obtain a mixture specific volume and a mixture specific enthalpy of the node; calculating the pressure of the node according to the mixture specific volume and the mixture specific enthalpy so as to monitor the characters of the steam and water of the node at the current moment. According to the method and system, the pressure of the node can be obtained independent of physical properties of the node, then, simulated data closer to field production are obtained, and operating personnel can more effectively guide the field production.