This study modeled some physical, chemical and biological characteristics in the Sea of Oman and investigated the effect of these characteristics on chlorophyll-a concentration using monthly data for different spans from January 1948 to October 2011. The statistical SPSS and R programs are used in this study. Attention is paid to the normality of the variables and their error, heteroskedasticity, trend and stationarity features. The relationship of chlorophyll-a concentration and other characteristics was found using different models. Forecasting procedure is implemented to compare the efficiency of these models. The results of this research suggest that there is relation between chlorophyll-a and sea surface height and sea surface temperature.