a method for preparing a pbat laminated membrane composite material uses pbat or a material with pbat as the main component and other biodegradable plastic or superfine calcium carbonate in a mixture . the temperature of the mixture is increased by means of a lamination machine segment by segment , the material is heated slowly to a molten state , and the temperature of a rolling shaft is controlled by introducing cold water to the rolling shaft when the lamination machine conducts membrane lamination , so that the temperatures of rolling wheels and the laminated membrane are controlled .