An optical touch device and a sensing method thereof are provided. The optical touch device includes a plurality of optical sensors and a processing unit. The optical sensors are arranged around a touch plane and are spaced from each other. The two adjacent optical sensors located at one side of the touch plane are defined as one set of an optical sensing module, such that the optical sensors are paired to form multiple sets of the optical sensing modules. The processing unit generates a plurality of touch coordinates data corresponding to the plurality sets of the optical sensing modules according to the optical touch data, and determines whether the touch coordinates data corresponding to each set of the optical sensing modules is in at least one touch-excluded area corresponding to each set of the optical sensing modules, and respectively excludes the touch coordinates data in the touch-excluded area.