The utility model relates to a supporting structure of fixed ball valve, a serial communication port, including valve body, spheroid, back shaft, one -way thrust ball bearing, slide bearing and gland, be provided with first shaft hole on the surface of spheroid lower part, be equipped with between the outer peripheral face of the one end of back shaft and the inner wall in first shaft hole slide bearing, the up end of back shaft with be equipped with one -way thrust ball bearing between the bottom surface in first shaft hole, the other end of back shaft with the valve body is connected, the gland is fixed on the valve body and to leaning on on the lower terminal surface of back shaft. In this application, because one -way thrust ball bearing can bear great axial load, and is right effective support has been realized to the spheroid, its with slide bearing cooperates the use, has realized the light pivoted effect of spheroid, effectively solved in the valve use spheroidal card hinder with moment of torsion increase problem.