In the marketing, there are some correlated between two complement materials when predicting the duration of manufacturing process. Two different kinds of materials are complementary if using more of one material requires the use of more of another. Thus, based on this view of point, when we estimate the production demand quantity, we can’t consider these two durations of manufacturing process as dependent. In this paper we propose the bivariate exponential distribution to model two related manufacturing durations of two complement materials. Finally, we demonstrate both MLE and moment methods to estimate the parameters of our model. This can provide the reference for the future study to choice a suitable estimation.