It is difficult to model those complicated objects around buildings, which will obviously affect the flow patterns and temperatures of the outdoor environment. In this paper new method is concluded to solve this kind of modeling problems. Those centralized objects are treated as porous media which will also affect the air flow and turbulence. New source terms are coded into the model to simulate the characteristics. In this way, we can easily model as many as influential factors into the simulation and save much computational time and get a satisfactory result. Plants and buildings are modeled in this paper and some preliminary conclusions are drawn. Good simulation results proves the feasibility of the model.