We have applied regression model together with statistical test, Pearson Correlation, to examine the relationships between aerosol optical depth (AOD), cloud optical depth (COD) and water vapor retrieved by Moderate Resolution Imaging Spectrometer (MODIS) in 2009 over Malaysia. It is shown that the relationship between water vapor in clear sky and AOD mean showed the highest significant compared to the others. Pearson Correlation showed that AOD and Water Vapor (Clear sky) have positive correlation but COD and water vapor (cloudy) have negative correlation, which both have significant correlation (p<0.01). Such regression model and correlation play an essential part in order to quantify the contributions in influencing climate change and global warming. However, analysis of the complex connection of AOD, COD and water vapor should be made with great care and further work is needed.