Abstract: The temperature and relative humidty control are very important in poultry houses. This paper introduces the design method and the operating conditions of a Pad-Fan Cooling ventilation system (P-FCVS) in poultry houses. The practices show that the system is very effective, even in the summer time of south China, where the whole day temperature is very high and the temperatare difference between day and night is small. Using P-FCVS in Poultry houses, the temperature can be controlled at a level of 30℃, and the relative humidity at 75-80%.After the high-temperature threatening have been removed, the relative humidityof 75-80% is no harmful consequences for poultry.The design method introduced in this paper is with definite conception and easiness of use, As the ventilation system used in this design is the longitudinal type which is unneeessary to use the large diameter fans. Thus it will save a great deal of energy consumption.