The invention relates to a thermal-decomposing pore-forming self-heat-insulating bearing sintered product and a preparation method thereof. The thermal decomposing pore-forming self-heat-insulating bearing sintered product mainly comprises the following raw materials of powder solid waste, a binder and a thermal-decomposing pore-forming agent in a mass ratio of 1: (0.5-1.5): (0.1-0.4), wherein thepowder solid waste adopts one of fly ash, coal gangue and tailings; the binder adopts shale or sodium soil; and the thermal-decomposing pore-forming agent adopts one salt or a mixture of calcium oxalate, basic magnesium carbonate, powdered whiting and dolomite which can be decomposed to discharge a great amount of gases at 500-900 DEG C. The preparation method comprises the following steps: adding water to granulate; aging for 1-3 days; forming blank blocks by a porous block mold in a vacuum extruder; drying at a temperature of 45-55 DEG C for 2-4 days; and sintering at 1000-1100 DEG C for 5-8 hours before cooling. The invention has the advantages of solid waste utilization, soil saving, good heat-insulating effect, convenient and rapid construction, and the like.