The invention relates to a preparation method of poly(sebacoyl diglyceride) shape memory elastomer. The preparation method \ comprises the following steps: (1) preparing a monomer sebacoyl glycidyl ester; (2) preparing poly(sebacoyl diglyceride); and (3) preparing the poly(sebacoyl diglyceride) shape memory elastomer. The crosslinking degree of PSeD is adjusted to make the crosslinked PseD have elasticity, shape memory effect and thermoplasticity; and the crosslinked PSeD has good shape memory performance, the shape transition temperature is between room temperature and the human body temperature, and the crosslinked PSeD is expected to be developed temperature response shape memory smart materials (the shape memory performance nearby the human body temperature is realized).