Grain refinement, randomization of texture and improvement of mechanical properties on AZ31B magnesium alloy were attempted by applying the wavy form rolling method. Specimens were heated at 523 K and then wavy form rolling, followed by reheating at the same temperature and rolled again. The wavy rolls were heated at 423 K by attached roll heaters. Cracking did not occur during wavy form rolling. This process was repeated 8 times, then the specimen was flattened using conventional flat rolls at room temperature and finally annealed at various conditions. Grain sizes in the specimens were determined by optical microscope. Textures formed in the specimens were analyzed by electron backscattered diffraction measurements. Mechanical properties in the specimens were evaluated by tensile tests. The wavy form rolling and decreasing rolling temperature were useful for randomization of texture. But annealing after wavy form rolling at higher temperature and for longer time caused the basal plane texture. Anisotropy in mechanical properties of the wavy form rolling specimens was decreased in comparison with those in the starting materials.