Abstract: Provided are an ohmic contact structure, a manufacturing method therefor, an HEMT device and an application thereof. The manufacturing method for an ohmic contact structure includes: providing an epitaxial layer for manufacturing an ohmic contact metal electrode; sequentially evaporating an adhesive layer and a covering layer at a position of the epitaxial layer corresponding to the ohmic contact metal electrode in a vacuum environment; exposing the epitaxial layer evaporated with the adhesive layer and the covering layer to the atmosphere to oxidize a metal material of a surface of the covering layer to thereby form a diffusion-blocking layer; sequentially evaporating a connecting layer and a protective layer on the diffusion-blocking layer in the vacuum environment; and annealing the epitaxial layer formed with the connecting layer and the protective layer at an environment temperature of 500° C.-600° C. to thereby form the ohmic contact structure.