The utility model discloses a window frame structure, and relates to the technical field of door and window equipment. Comprising a first blocking part, a second blocking part, a first sealing piece and a second sealing piece, the second blocking part is fixedly arranged on the hole wall of a wall hole where a window is located, and the first blocking part and the second blocking part are integrally connected and arranged in the direction of the center position of the wall hole; the first sealing piece is arranged on the side surface, facing the window, of the first blocking part, the second sealing piece is arranged on the side surface, facing the window, of the second blocking part, and the first sealing piece and the second sealing piece are matched to form the double-sealing waterproof structure. According to the window frame structure, the sealing pieces are arranged on the two blocking parts of the frame structure respectively, so that a window can be blocked by the two blocking parts at the same time, and the window closing effect is achieved; after the window is closed, the window abuts against and makes contact with the two sealing pieces at the same time, then two seals are formed between the window and the frame structure of the window, and the anti-leakage performance of the window is improved.