A touch apparatus and a sensing method and a touch sensing circuit thereof are provided. The touch apparatus includes a touch panel and the touch sensing circuit. In a first period, the touch sensing circuit applies the same driving signal to a plurality of sensing electrodes of the touch panel at the same time, and performs self-capacitance touch detection on the sensing electrodes to obtain a self-capacitance detection result. In a second period, the touch sensing circuit performs mutual-capacitance touch detection on at least one of the sensing electrodes to obtain a mutual-capacitance detection result. The touch sensing circuit determines whether a touch event of the touch panel is triggered by water based on the mutual-capacitance detection result and the self-capacitance detection result.