Rotation angle is a key parameter in the processing of three-roller, cold-rolled seamless steel tubes. Using a cold-rolled AZ31 magnesium alloy tube as the research object .Based on the cold-rolling process under different rotation angles, the present paper conducts a comparison and analysis of the effects of different rotation angles on the characteristics of the deformation equivalence effect force, equivalent plastic strain and regularity of the influence of node temperature. Our study shows that increased rotation angles increase the equivalent stress, equivalent plastic strain and node temperature. With the aid of the automaton model and experimental means ,through the experiment and numerical simulation results contrast analysis, the author finds out the grain produced in the process of rolling in the continuous refinement of recrystallization and preliminary organization evolution law. The results reveal that a 50° rotation angle can sufficiently meet technical requirements and provide evidence for the appropriate selection of rotation angles for cold-rolled magnesium alloy tubes.