This study confirms that the symmetric plane of (001) with respect to the twin boundary in β-Ga2O3 is the (1¯01), and it has been systematically characterized. X-ray diffraction has determined that diffraction peaks appear only at positions where the l component of the miller indices hkl is even, and these positions coincide with the diffraction peak positions of the (001) plane. The termination atomic arrangement of the (1¯01) plane is not exclusively composed of gallium or oxygen atoms, it exists in two forms with hanging bond densities of 1.614 × 1015/cm2 and 2.421 × 1015/cm2, respectively. Wet etching experiments on the (1¯01) plane reveal distinct defect morphologies compared to the (001) plane, indicating its suitability for distinguishing between these two planes. The Raman modes of (1¯01) plane coincide with other crystal planes. Through optical transmission spectra, X-ray photoelectron spectra, and Ultraviolet photoelectron spectra, its bandgap width Eg of 4.76 eV, the valence band maximum EVBM of 3.64 eV and the Schottky barrier height Φsurf of 1.12 eV were determined. Compared to studies of other crystal planes, it is believed that the (1¯01) plane also possesses similar application potential.