In order to numerically study the condensation and comfort of the downward directed vertical wall jets and floor radiation composite air conditioning system,the thermal environment of the system was simulated by Airpak3.0.The indoor composite air conditioning model was established by using the measured data as the boundary condition.Design relative humidity, air supply speed and air outlet position were analyzed in order to get the influence on indoor thermal environment.Relative humidity, PMV and PPD characteristics under various indoors working conditions were qualitative analyzed. It provides a reference for the reasonable operation design of the downward directed vertical wall jets and floor radiation composite air conditioning system.