The invention discloses a protecting device for a buried pipeline. The protecting device comprises a main pipe and a sleeve. The main pipe is inserted into the sleeve. A cover plate is arranged at the junction between the main pipe and the sleeve. The diameter of the cover plate is larger than that of the sleeve. The space between the edge of the cover plate and the sleeve is wrapped with flat steel. Radial springs are installed between the main pipe and the sleeve in the circumferential direction. Axial springs are arranged between the sleeve and the cover plate. According to the protecting device for the buried pipeline, through the arrangement of the cover plate and the flat steel, the heat preservation effect and the heat tracing effect of a main pipeline are improved, the displacement difference caused by thermal expansion between the main pipeline and the sleeve can be eliminated, and small animals such as rats can be prevented from entering the sleeve.