This paper describes phase behavior simulation of complex process station in the light and volatile oil reservoir simulation, using equation of state method. The technology process of the station includes two-stage separation, crude oil stabilization, three-phase separation, shallow cooling, deethanization and debutaiuzation. In the new compositional model, the simulation of surface complex process station is considered with combination of reservoir simulation based on uniform parameters of equation of state. The differential flash method and nested successive substitute iteration method have be used for solving dynamic phase equilibrium problem for deethanizer and debutanizer in the simulator. The simulator also considered process and product quality controls. The simulator provides calculation results for production of stabilized oil, sale dry gas, light oil, naphtha and LPG. It is very useful for light oil and volatile oil reservoir simulation.