Leakage-proof valve for mortar environment

The invention relates to the fields of well completion and production of petroleum and natural gas, in particular to a leakage-proof valve for a mortar environment. An outer layer component sleeves the outer side of a whole, formed by an inner layer component and a switching mechanism, in a sealing way; the switching mechanism is in elastic connection with the outer layer component; an upper jointand a lower joint are separately in threaded connection with the outer layer component; the upper joint is connected with the inner layer component in a sealing way, and the lower joint is connectedwith the switching mechanism in a sealing way. The switching mechanism is designed in a closed space, so that the problem of blockage, caused by solid particles such as sand, of the switching mechanism is fundamentally solved; the surfaces of a spherical body and a spherical seat are coldly sprayed with cemented carbide, so that the wear resistance of the leakage-proof valve is improved; the innersurface of the whole tool