The invention relates to a method of rheologically casting and rolling an AZ91D magnesium alloy sheet with a rotating tube, belonging to the field of the metal casting. The method of rheologically casting and rolling the AZ91D magnesium alloy sheet with the rotating tube is characterized by comprising the following steps: melting AZ91D magnesium alloy in a melting furnace until the molten AZ91D magnesium alloy being 740-760 DEG C; adding C2Cl6 to the molten AZ91D magnesium alloy to modify the molten AZ91D magnesium alloy, reducing the temperature of the molten AZ91D magnesium alloy to 615-675DEG C; stirring the molten AZ91D magnesium alloy, scattering refining agent on the wave crest of the molten AZ91D magnesium alloy to refine the molten AZ91D magnesium alloy for 15-20 min, reducing the temperature of the molten AZ91D magnesium alloy to 615-675 DEG C, and keeping the temperature of the molten AZ91D magnesium alloy at 710-730 DEG C; preheating a rotating pipe to 80-150 DEG C, controlling the angular speed of the rotating tube at 40-110 r/min, and regulating the inclination angle of the rotating tube to 15-35 DEG; guiding N2 and 0.4 percent SF6 to the molten AZ91D magnesium alloy; preheating a guide to 80-100 DEG C, and pouring the molten AZ91D magnesium alloy into the rotating pipe by the guider; preheating a casting nozzle to 350-450 DEG C, controlling the rotating speed ofcasting and rolling rollers at 6-13 r/min, the temperature at 100-150 DEG C and the gap at 0.5-4 mm; filling the casting nozzle with the slurry by feeding the slurry flow evenly, and continuously casting and rolling the AZ91D magnesium alloy sheet in a casting and rolling area. The invention causes lower thermal impact, little thermal etching to the casting and rolling rollers, thereby prolongingthe service lives of the casting and rolling rollers.