The utility model relates to an air line structure for a hydrotherapy bathtub. The air line structure comprises an air inlet pipe, an air distributing and exhausting network and an air hood; the air distributing and exhausting network is arranged on a tub body of the bathtub and is located below a bathing liquid surface of the bathtub; the air distributing and exhausting network comprises a plurality of air distributing and exhausting holes which are arranged on the tub body of the bathtub and communicate the inner side of the tub body with an air inlet space of the air distributing and exhausting network; the air hood is in closed connection with the horizontal upper surface of the tub body of the bathtub so as to form an inlet air allocating space; and the air inlet pipe and the air distributing and exhausting network are respectively communicated with the inlet air allocating space so as to enable the air inlet pipe and the air distributing and exhausting network to be communicated with each other. The air line structure for the hydrotherapy bathtub has the advantages that the accident that bathing water refluxes into an ultrasonic host is reliably prevented, non-return valves are not required for being arranged on an air line, the air line structure is simplified, the cost of manufacturing, mounting and maintaining is reduced, the free switching between inner tub body air inlet and bathtub inner sleeve air inlet is realized, the structure is simple, the closeness is reliable, the dismounting storage of a bathtub inner sleeve is facilitated, and the use is convenient.