The walnut kernel was ball milled for different durations (2, 4, 8, 16, and 24 min) to develop walnut butter products, reduce the particle size and improve its rheological properties. The average particle diameter of walnut butter after ball milling for 24 minutes decreased from 79.89 μm to 37.88μm, by 53% overall. It was a typical non-Newtonian pseudoplastic fluid, which had the characteristics of viscoelasticity and positive thixotropy. The results revealed that the hardness and consistency of the walnut butter decreased, and the fluidity gradually increased during the ball milling treatment. The walnut butter ball milled for 8 minutes showed the higher viscosity and smaller in particle size, and was suitable for processing as a spreadable butter. As for ball milling process for 16 and 24 minutes exhibited the best fluidity and was suitable for the processing of salad sauce. Results could be useful in development of the walnut butter making process system design. Therefore, high-energy ball milling technology could be used as a technique for preparing walnut butter, and gradually change the rheological properties of finely divided walnut butter through the process.