Anti-shearing protective sleeve for steel-plastic adapter

The utility model discloses an anti-shearing protective sleeve for a steel-plastic adapter. The anti-shearing protective sleeve comprises a thin pipe section, a thick pipe section, a reducing section and a connecting section. The thin pipe section is connected with the plastic end; the thick pipe section is connected with a steel pipe end; the reducing section is located between the thin pipe section and the thick pipe section, and the reducing section is connected with the thin pipe section and the thick pipe section in an arc transition mode. The connecting section is arranged at the end of the thick pipe section and detachably connected with the thick pipe section. The utility model provides a long-service-life anti-shearing casing which allows an anti-shearing protective casing to slightly deform through a radian transition section preset in advance so as to release part of stress. The problems that in the prior art, protection cannot be achieved due to the fact that a gap exists between a PE sleeve and a