The invention provides an improved buoyancy tool structure which comprises a body. The body comprises a first combination and a second combination, wherein, an air drain and a cladding slot are arranged inside at least one of the first combination and the second combination; the body leads the first combination and the second combination to be welded and combined with ultrasonic welding mode; a driving piece is arranged in the cladding slot; after the first combination and the second combination are welded and combined, the air drain becomes an air chamber in sealed state and is filled with proper air; the first combination forms a concave section on the external end surface of the cladding slot; the second combination forms a convex section on the external end surface of the cladding slot; and the concave section and the convex section are in paired welding for strengthening the tightness of the body molding. By adopting the structure, the body has floating effect, and the inside of the body achieve completely closed and sealed without water leakage and seepage, thereby improving the convenience of operation.