The invention discloses a semiconductor heterostructure, and a preparation method and applications thereof. The semiconductor heterostructure comprises a first semiconductor material and a second semiconductor material. The first semiconductor material and the second semiconductor material are mutually joined to form virtual lattice matching. The first semiconductor material is AlxInyGa1-x-yN, wherein 4.72< / =x / y< / =5.10, 0< / =x< / =1 and 0<y<1. The second semiconductor material is GaN. Preferably, 0.2<(1-x-y)< / =0.6. The preparation method comprises steps: after a GaN layer is formed through growth, an AlxInyGa1-x-yN layer is formed in a mode of introducing an aluminum source, an indium source, a gallium source and a nitrogen source in a reaction chamber of epitaxial growth equipment in a simultaneous and / or pulse means. By using the semiconductor heterostructure of the invention, the production process of a semiconductor device can be effectively simplified, the reliability of the semiconductor device is optimized, and particularly, the reliability problem of devices such as an HEMT due to stress can be eliminated fundamentally, and more ideal spontaneous polarization strength between the barrier layer and the GaN layer can be kept.