Fabricating the p-n junction and exploring the device physics play key roles in developing various functional devices and promoting their practical applications. Although ultrawide bandgap semiconductors have great potentials to fabricate high-voltage and high-efficiency power devices, the lack of p-type Ga2O3 poses a fundamental obstacle for fabricating the Ga2O3 p-n homojunction and impedes the development of full Ga2O3-based bipolar devices. In this study, n-type Sn-doped β-Ga2O3/p-type N-doped β-Ga2O3 films are prepared by a novel phase-transition growth technique combined with sputter deposition. Full β-Ga2O3 one-sided abrupt p-n homojunction diodes are fabricated and the device physics are explored in detail. The diodes possess a high rectification ratio of 4 × 104, a low specific on-resistance of 9.18 mΩ cm2 at 40 V, a built-in potential of 4.41 V, and an ideal factor of 1.78, and also show a good rectification behavior under alternating voltage with no overshoot and longterm stability. Our results clear away the major obstacle to β-Ga2O3 p-n homojunction, lay the foundation for β-Ga2O3 homogeneous bipolar devices, and pave the way for the evolution of high-voltage and high-power device applications.