Successful application of one-dimensional advection-dispersion models in rivers depends on the accuracy of longitudinal dispersion coefﬁcient (LDC). In this regards, this study aims to introduce an appropriate approach to estimate LDC in natural rivers that is based on a hybrid method of granular computing (GRC) method and artificial neural network (ANN) model (GRC-ANN). Also, Adaptive Neuro-Fuzzy Inference System (ANFIS) and ANN models were developed to investigate the accuracy of three credible Artificial Intelligence (AI) models and the manner of these models in different LDC values. By Comparing with empirical models developed in other studies, the results revealed the superior performance of GRC-ANN for LDC estimation. The sensitivity analysis of the three intelligent models developed in this study is done to determine the sensitivity of each model to its input parameters specially the most important ones. The sensitivity analysis results showed that the W/H parameter has the most significant impact on the output of all three models in this research.