A naphtha price forecasting model based on the time series method is developed to predict the monthly variation of naphtha price using statistics. We used the model to forecast future naphtha prices by looking at historical time series data from January 2008 to September 2011. After forecasting, we perform the normalization of the observed period and implement a simulation using the price forecasting model. In order to check the accuracy of the model, the predicted naphtha price variations are compared with the actual naphtha variation. If the predicted variation of the normalized naphtha price has the same trend as the actual naphtha variation, our prediction value is called "T." Otherwise, the predicted value is called "F." The accuracy of the predicted value is relatively higher than the price forecasting for other products such as crude oil. As a result, our model is useful to industry decision-makers for forecasting the price of naphtha.