Clod/hot two-way protecting device and method for steam and pipeline

The invention discloses a clod/hot two-way protecting device and a clod/hot two-way protecting method for steam and a pipeline. The clod/hot two-way protecting device is applied to the technical field of pipeline transport and condensation and overheating prevention. The clod/hot two-way protecting device comprises a thermal insulation material layer, a phase-change material layer, a memory alloy layer, memory alloy wires and phase-change material capsules. The influence on the pipeline and the steam from an outer circumstance temperature is reduced by employing the thermal insulation material layer; the temperatures of the pipeline and the steam are kept unchanged in a low temperature environment for a long time by employing solidification heat release of the phase-change material layer, and the pipeline is prevented from being corroded by steam condensation; and an overheating phenomenon is avoided since a memory alloy net attached to the outer wall of the pipeline and the phase-change material capsules con