We investigated hydrogen sensing characteristics of semipolar (11-22) GaN Schottky diode, and compared to various crystal planes of GaN including conventional gallium polar c-plane (0001), nitrogen polar c-plane (000-1), and a-plane (11-20). The semipolar GaN diode showed remarkable current change to 4% hydrogen in nitrogen and the device exhibited full recovery into original current level under nitrogen ambient. Each plane has its own surface configuration and shows different hydrogen responsivity. In case of (11-22) plane GaN, its current response to hydrogen is very large even though its surface is terminated with gallium atoms, since active nitrogens position beneath the gallium atoms.