Abstract: Embodiments of the present invention relate to an epitaxial structure of a semiconductor device and a manufacturing method thereof, and a semiconductor device. The epitaxial structure of the semiconductor device comprises: a substrate; and an epitaxial layer located on one side of the substrate, the epitaxial layer comprising at least a first sub-epitaxial layer group, the first sub-epitaxial layer group comprising a first sub-epitaxial layer and a second sub-epitaxial layer arranged in stack; wherein, a surface of one side of the first sub-epitaxial layer away from the substrate comprises a plurality of first dislocation pits, and sidewalls of the first dislocation pits intersect both a plane where the first sub-epitaxial layer is located and a first direction; and the second sub-epitaxial layer covers at least the sidewalls of the first dislocation pits.