An embodiment of the present application provides a preparation method of a mask assembly, including: fixing, after stretching and aligning a blocking, the blocking on a side of a frame; opening at least one stretching align hole and at least one evaporation align mark in the fixed blocking and frame; fixing, after stretching and aligning a mask sheet, the mask sheet on a side of the blocking away from the frame according to the stretching align hole; and opening at least one evaporation align mark in the fixed mask sheet to obtain the mask assembly.