Self-pressure-relief low-temperature ball valve

The invention provides a self-pressure-relief low-temperature ball valve which is suitable for a pipeline passage at low temperature, the ball valve comprises a valve rod, a valve body and a ball body, one end of the ball body is fixedly connected with the lower end of the valve rod, the ball body is arranged in a valve cavity of the valve body, and a ball body inner cavity of a hollow structure is formed in the ball body; the valve cover is of a cavity structure and is arranged at the top of the valve body, the valve rod is arranged in the cavity structure of the valve cover, and a gap area is formed between the valve cover and the valve rod; and the pressure relief passage is sequentially communicated with the gap area, the inner cavity of the ball body and the valve cavity, so that the same pressure intensity is kept among the areas. The valve has the advantages of being simple in structure, convenient to operate, good in sealing performance, long in service life and the like, and is suitable for fluid con