Abstract: Embodiments of the present application relate to the technical field of semiconductors, and provide a manufacturing method for an N-polar GaN transistor structure and a semiconductor structure. A Ga-polar epitaxial functional layer is formed by depositing, a supporting substrate is formed on the epitaxial functional layer by bonding, after the epitaxial structure is inverted, a structural substrate and a buffer layer are removed, and a source, a drain, and a gate are manufactured on the side of the exposed epitaxial functional layer away from the supporting substrate, to form an N-polar GaN transistor structure.