In order to improve the compatibility and mechanical properties of starch/polybutylene succinate (PBS) blends, using glycerol and 1-butyl-3-methylimidazolium chloride ([BMIM]C1) as modifier, the corn starch/PBS blend materials were prepared by melt blending method, and the effects of compound modification on the structure and properties of starch/PBS blends were studied by infrared spectroscopy, X-ray diffraction, scanning electron microscopy, differential scanning calorimetry and mechanical test. The results show that the compound plasticizer has well modification effect on corn starch/PBS blends, and the modification effect is related to the composition ratio, With the increase of [BMIM]Cl content in the modifier, the elongation at break of the modified starch/PBS gradually increases, when the mass ratio of [BMIM]Cl to glycerol is 9:1, the elongation at break of the blend is the highest, showing a stronger modification effect than glycerol or [BMIM]Cl. Glycerol/[BMIM]Cl modifies starch/PBS mainly by changing the hydrogen bonds of hydroxyl groups and enhancing the interaction between starch-modifier-PBS molecules, which can improve the compatibility of starch and PBS, and reduce the crystallinity of blended materials. Under the condition that the tensile strength of the blended material does not change much, the elongation at break of the blended material is significantly improved. Stretching of starch/PBS blends (starch accounts for 40% of the total mass of starch and PBS) prepared with glycerol/[BMIM]Cl (mass ratio 9:1, adding 35% starch mass) as modifier, the strength is 17.53 MPa and the elongation at break can reach 211.50%.