The invention belongs to the technical field of planing boats, and particularly relates to a planing boat with a three-channel structure. The planing boat is the further improvement on a channel planing boat. Due to adoption of the design of three channels, bow made waves and wave loads can be absorbed during high-speed sailing, meanwhile, slamming loads of waves at the bow of the planing boat arereduced, planing postures are improved, and the sailing stability of the planing boat is improved. During high-speed sailing of the planing boat, an air film and a splashing water flow layer can be formed in each channel, and loads caused when waves directly slam the bow are reduced. Front air incoming flow can be guided to the boat bottom through the channels, accordingly, a boat body is elevated, drinking water of the boat is reduced, and the sailing resistance of the planing boat is reduced. The width of the channel at the middle portion is larger than the width of the channels on the twosides, the height of the channel is larger so that front incoming air can be widely absorbed to the bottom of the boat body, and meanwhile due to the large channel width, the made waves generated by amain boat body can be further absorbed.