To address the complex handover problem in multi-layer heterogeneous integrated networks （MLHetINet）， this paper develops a staring beam and interference cancellation algorithm to get valid data for handover analysis， simplifies the beam alignment and acquisition process， expands the coverage of the air-based network， and reduces the complexity of cross-layer handover. Firstly， aiming at the relatively high-speed movement between the ground terminal and the air base station， this paper develops a dynamic staring multi-beam forming algorithm to adaptively adjust the antenna phase and weight， and generates the main lobe in the target direction and the zero-trap for the interference source to achieve airspace isolation， thus simplifying the complexity of handover analysis. Then， considering the complexity of the air-ground channel， a multi-order interference cancellation algorithm based on column norm grouping sorting is proposed to further improve the detection accuracy of the target signal and the accuracy of handover analysis. Finally， based on the staring beam and interference cancellation algorithm， an independent handover protocol is designed for handover events in the space-air-ground three-dimensional MLHetINet， which significantly reduces the consumption of network resources. Through simulation， it is verified that the user information rate in the three-dimensional MLHetINet is significantly improved compared with that in the traditional ground network and space-ground integrated network.