Abstarct: With regard to recent developments in the field of Nano-Fluids and the subject of Micro-Nano bubble, laboratory research is conducted for investigating the formation of air Micro and Nano bubbles in venturi tube with image processing method. In this research, a venturi tube was made in laboratory scale and by using new image processing methods, hydrodynamic characteristics like the surface occupied by bubbles, the velocity of the bubbles and the amount of dissoluted air in water were studied. The velocity of bubbles varies in different regions of Venturi, therefore to measure the characteristics of the bubbles; a camera (with capability of 4500 frxames per second) with MATLAB software were used. By the appropriate threshold, the area of the water, the bubbles and the injected air are calculated. The experiments were carried out for three flow rates of 0.16, 0.29 and 0.42 liters per second. The results of the experiments and image processing in the two regions of the Venturi’s bottleneck and before the Venturi’s bottleneck indicate that decline in pressure and dissolution of air in the water are according to the Henri’s equation. The velocity of the bubbles in the Venturi’s bottleneck increase by the pressure decline. After the Venturi’s bottleneck, the pressure and dissolution of the air in the water decrease and the velocity of bubble increases. In addition, the results of the experiments show that by increasing flow rate, the bubbles become smaller and the possibility of micro and Nano bubbles formation in Venturi increases.