Bottom ball valve is applied for discharging reactor containers in pharmaceutical, biological, fine chemical, food and other clean industries. It has the advantages of no dead angle, no residue, no leakage and good sealing performance. When apply the agitator in container, the bottom material of the agitator can fully rotate with the water flow when it is opened to make the material mix evenly. The 35 degree installation position of the valve can make the discharging material have self-purification function and make the equipment maintenance more convenient in space. The mirror polishing roughness in the valve is 0.2-0.45 um, which makes the valve cleaner.