Multi-stage flash (MSF) desalination is the main process to solve the problem of limited freshwater resources in the world. This work describes the developed steady-state mathematical model for analysing and evaluating the performance of Multistage flashing with brine circulation desalination process (MSF-BC). It is based on the laws of energy balance, material balance, and heat transfer equations with physical properties correlations equations. The nonlinear equations are linearized and arranged into a tridiagonal matrix form. The model solution is obtained by a computer code written by MATLAB program software. It can predict the productivity of the plant with temperature profiles and flow rates for all stages in the unit. The model results were compared with some previous results presented in literature. The comparison shows good agreement with these available data. An MSF desalination plant in Ayoun Mousa, Egypt of capacity 5000 m 3 /day was presented as a case study.