The invention discloses a floating ball valve. The floating ball valve comprises a valve body, a gland, a valve rod and a sealing structure; the gland is fixed on a top opening of the valve body; a first mounting space is formed between the bottom surface of the gland and the top opening of the valve body; the top of the valve rod penetrates through the gland and the first mounting space to extend in an inner cavity, and is connected with a driving mechanism; the sealing structure is pressed in the first mounting space by the gland, and includes a support body; and the support body sleeves the valve rod, the inner surface thereof is connected with the valve rod through a first sealing piece thereon in a sealing way, and the outer surface thereof is connected with the inner wall surface of the valve body through a second sealing piece thereon and/or a second sealing piece arranged on the inner wall surface of the valve body in a sealing way. Even though the valve rod rotates, the valve body does not rotate, the position of the gland fixed on the valve body is invariable, the positions of the first sealing piece and the second sealing piece arranged on the support body are not changed, and the first sealing piece and the second sealing piece can be respectively clamped on the outer wall surfaces of the valve rod and the support body to keep a sealing state.