In this work, A 3-dimensional model is developed to investigate fluid flow in a magneto-hydrodynamic micropump. The equations are numerically solved using the finite volume method and the SIMPLE algorithm. This study analyzes the performance of the magnetohydrodynamic micropump. For this purpose, a magnetohydrodynamic micropump built in 2000, is simulated. The micropump has a channel with 20mm length, width of 800 , height of 380 and an electrode with 4mm length. The applied magnetic flux density was 13mT and the electric current was different for various solution (10-140 mA). The results show that the intensity of the magnetic field, the electric current and the geometry has an effect on the magnetohyrodynamic micropump performance. By increasing the amount of magnetic flux and electric current the average velocity increases. decreasing the channel length would increase the mean flow velocity. by increasing the channel depth, the mean flow velocity initially increases and then decreases, while at a depth of approximately 700-800 the maximum averaged velocity will be resulted. The velocity increases by Increasing the channel width to 1500 , however the velocity remained unchanged for larger values.