The topographical condition of the three-dimensional model domain was commonly neglected in odor dispersion modeling studies. This limitation makes the use of odor dispersion model with flat terrain an unappropriated model to be used in mountainous and hilly test areas such as in the case of South Korea. To account for this, the study developed a three-dimension CFD model with complex topography to predict odor dispersion. Considering that the length and the amount of odor emitted from pig houses were influenced by various external factors, this research aimed to analyse the influence of ventilation types, atmospheric stability, wind speed and wind directions on the movement of odors outside the pig house facilities. A grid test and turbulence independence test were used to validate of the CFD model was made by comparing the experimental data and the CFD calculated results. The field measured data was obtained from a commercial full-scale pig facility. Result showed that the appropriate grid size and turbulence model to be used in calculation were 4 m and k-ε turbulence model respectively. Statistical analysis of the datas determined that the most influential factor that affects odor dispersion was the wind speed followed by atmospheric stability, ventilation type and wind direction with a rescaled relative weight of 58.17%, 23.20%, 17.91% and 0.73%, respectively. Accordingly, low wind speeds influenced the highest odor dispersion. This effect is more pronounced when the atmospheric condition is stable, ventilation type uses side exhaust fan and windward and leeward wind passes from location with flat terrain.