To explore the effect of black bean protein isolate on the gel properties and microstructure of corn starch with different amylose/amylopectin ratio. Common starch （CS） and high amylopectin starch （HAS） derived from corn were used as raw materials， the effect of adding black bean protein isolate（BBPI）（10 ∶ 0，9.5 ∶ 0.5，9.0 ∶ 1.0，8.5 ∶ 1.5，8.0 ∶ 2.0， CS （HAS）/BBPI） on the gelatinization， dynamic rheological properties， static rheological properties， texture properties and microstructure of the blend system was discussed. The results showed that the addition of BBPI had a significant effect on the gel and structural properties of CS（HAS）/BBPI system， and the effect on the CS system was greater. With the increase of the proportion of BBPI， the peak viscosity and retrogradation value of CS/BBPI and HAS/BBPI systems were decreased gradually， and the pasting time was delayed； the storage modulus and loss modulus of the system gradually reduced， and the tanδ increased first and then decreased， the gel strength was weakened and the shear stress of the system reduced to varying degrees； the hardness and cohesiveness of gel system were decreased. Microscopic morphology characterization found that the CS（HAS）/BBPI gel network structure less dense， blurred in outline， larger pores， thinner pore walls and debris aggregation appeared with adding BBPI. Therefore， in the process of starch-based food processing，BBPI could be added in an appropriate amount to reduce the degree of product retrogradation and improve product nutrition and quality.