Turning-connection piece

The utility model relates to a turning-connection piece. The turning-connection piece comprises a first connecting part and a second connecting part. The first connecting part is provided with a thread installing hole, and the second connecting part is provided with annular grooves. The inner walls, located outside the annular grooves, of the second connecting parts are provided with annular seal grooves, and the bottom wall surfaces of the annular seal grooves are arranged into slopes. The second connecting part is provided with the two annular seal grooves, and the bottom surfaces of the annular seal grooves are concaved inwards with the central lines of the bottom surfaces as the axes. When the turning-connection piece is used, the parts, which are enlarged due to deformation, of the bottom portions of articles in the annular grooves can be contained in the bottom wall slopes of the annular seal grooves, and the articles can be unlikely to extrude the space formed by the annular grooves through the turning-connection piece. Seal rings can be arranged in the annular seal grooves during the turning-connection piece using process to play a sealing role, and therefore the overall sealing performance of the turning-connection piece is improved.