The effect of the heterogeneous material superlattice structure on carrier ionization rate was studied based on the collision ionization theory,and then the avalanche photodiode with In0.53Ga0.47As/In0.52Al0.48As superlattice was designed.Through analyzing the influence of different structural parameters on the device performance,the superlattice avalanche layer with low tunnel current and high multiplication factor was obtained.The relationship between two dimensional electric field distribution and charge layer thickness or doping was studied based on the electric field distribution equation,and the structural parameters of the absorption layer were optimized.Compared with ordinary avalanche photodiode,the optimized superlattice avalanche photodiode has stronger photocurrent response,and superlattice avalanche photodiode has high multiplication factor and low dark current in the avalanche multiplication area of 12.5~20 V,which greatly enhance the signal to noise ratio of the device.