A distributed parameter mathematical model was established for a finned tube condenser under steady state,and the actual flow condition was taken into consideration inside the condenser in this model,such as pressure drop and flow patterns. Simulation program of the finned tube condenser was written with the Visual Basic language. Comparisons were conducted between simulation results and data from experiment in the literature. The results showed that good consistency of the model. Based on this model,the characteristics of the flow and heat transfers of low GWP (Global Warming Potential) working fluids,R290,HFO1234yf and HFO1234ze in the finned tube condenser were simulated. When the head-on wind speed,mass flow rate and pipe diameter size were altered,the changes of refrigerating capacity and pressure drop were analyzed and the performance comparisons between the above low GWP refrigerants and R410A now widely used were carried out. The results showed that R290 had the biggest heat exchange capacity and HFO1234yf had the smallest under steady wind speed. HFO1234yf and HFO1234ze reached super-cooled state most easily in the same case. When pressure drops were the same,mass flow rate of R410A was the maximum and that of R290 was the minimum. When heat exchange capacity was the same,mass flow rate of HFO1234yf was more than the others and R290 was smaller than the others. The model could provide theoretical basis for the optimization design and system matching of low GWP refrigerant finned tube condenser and the refrigerant alternatives.