Rivers as the main water source for humans and other creatures are sometimes this source of life are polluted with entering the wast water that be caused a significant decreasing of dissolved oxygen. It is necessary to predict the amount of dissolved oxygen for management of water resources. So, estimation the amount of dissolved oxygen concentration, is one of the necessary steps to monitor river health.The various models have been developed in order to predict the dissolved oxygen in the rivers such as CSP and MSP models. The base of developed model in this research is advection-diffusion equation (ADE) of solute traort. For this purpose, two terms including production and decay of dissolved oxygen were added to this equation. Final equation was discretized using finite difference method with implicit scheme. With applying the initial and boundary conditions, the equation set was solved by Thomas algorithm. The calculations was done by programming in MATLAB software. After mapping the topography of the river, using GIS software and HEC-GeoRAS river sections and the results of its application moved to HEC-RAS. To get the velocity and depth of the river was used HEC-RAS software. In order to calibration and validation of the model, data of Zayanderoud were used. The temporal and spatial variations of dissolved oxygen were plotted and compared with real data and results of the MSP and CSP models. Results showed that concentration of the dissolved oxygen can be well predicted through solving developed ADE equation with introducing two terms for decay and production of oxygen. The comparison between the results of the model and two other models showed that the model gives better results than the MSP and CSP models. Sensitivity analysis of model coefficients showed that rearation coefficents had the most effect on results of the developed ADE model. The results showed the presence of type of different wires in suitable sections, causing a significant increase in the concentration of dissolved oxygen, but the kind of sharp-edgedweirs and compound weir at 5% level showed no significant difference. However, broad- crested and stepped weirs were effected on the concentration of dissolved oxygen. Also the weir-gate had no significant effect in 5% level on the concentration of dissolved oxygen. Keywords dissolved oxygen, Thomas algorithm, Zayandehrud, Advection- Dispersion Equation, overflow, MATLAB and HEC-RAS