The invention relates to a method for rolling a magnesium alloy extruding sheet strip plate which has the following steps: heating and heat preservation are carried out; a magnesium alloy cast ingot is heated to the temperature of 350 to 420 DEG C and heat is preserved; simultaneously, an extruding cylinder and an extruding die of the sheet strip plate are heated and the heating temperature is the same as that of the magnesium alloy cast ingot; heat preservation is carried out for 3 to 6 hours; extruding the sheet strip plate: the die is put into a die holder; the cast ingot is put into the extruding cylinder to be extruded; the extruding speed is 1.5 to 3m/min; rolling the sheet strip plate: the magnesium alloy sheet strip plate is pulled to the inlet location of a rolling machine by a tension roll and starting the rolling machine. The method of the invention can be adopted to continuously extrude a plurality of magnesium alloy cast ingots into a whole sheet strip plate and has the advantages of high material yield, convenient subsequent coil rolling, simple technique and less heat energy consumption.