Valves are common parts in all industries dependent on the fluid. Its duty is cutting or making flow, speed or pressure or flow direction control or is a combination of the above. Non-Newtonian fluids, especially polymer fluid has more complex viscosity model. The viscosity of this fluid is not constant not only change with temperature but also change with shear rate inside a duct. In this thesis is tried to pass a non-Newtonian fluid of molten polymer through a combination check valve. Important parameters that are considered in the design of this type of valve include: size, low pressure drop, no parts at zero speed and low speed fluid, uniform pressure distribution, proper viscosity model, uniform temperature distribution. Using equations of rheology, valve size was calculated.The valve size and shape was optimized by simulation results. Appropriate Drawing was desighned for valve. Valve body material selected from steels standard 1.6582. To prevent from rust hard chrome-plated was used. Final testing of valve with PVC polymer was carried out at 200 °C At first path 1 tested. Material easily passed this path. Then heating elements became off and polymer melt inside the valve solidified. Again Extruder machin turned on and temperature reached 200 °C. At this stage, the material easily passed from the first path. This test was repeated for the second path. Appropriate test results were satisfactory. ressure drop was lower in comparison with simple check valve and it had a good agreement with the results of mathematical calculations. Diameter of 12 mm after optimization had lowest areas of low or zero velocity. All paths had uniform pressure distribution. In all points of the model viscosity was simulated correctlly and Viscosity and shear rates distribution was reasonable. By use of suitable thermal elements, temperature inside the valve was Uniforms. Various standards were used to determine characteristics of the combine valve. Tests to determine the valve flow coefficien Cv(valve coefficient is valve flow capacity according to US gallons of water per minute at 60°F that passed inside the valve when the pressure drop across the valve is 1 PSI) by water and seat leakage test with air compared with simulation results. Seat leakage in the range of ISO 5208 standard was acceptable. The results are satisfactory. Keywords: Combine Valve, Non-Newtonian fluid, pressure drop, simulation by Ansys CFX.