The invention relates to a compound foaming stabilizer and a preparation method for the compound foaming stabilizer for producing a self-insulating lightweight concrete block. The method comprises the following steps: 1) enabling paracumyl phenol to react with ethylene oxide under the protection of nitrogen, synthesizing paracumyl phenol polyoxyethylene ether with polymerization degree of 6-14 to be taken as a main active ingredient of the compound foaming stabilizer; 2) mixing the paracumyl phenol polyoxyethylene ether with a defined amount of fatty acid salt and then adding a defined amount of solvent, thereby acquiring the compound foaming stabilizer suitable for chemical foaming. When the compound foaming stabilizer is used for preparing the self-insulating lightweight concrete block, the additive amount is 0.04% of the weight of cement, the dry density of the block is 0.61g/cm3 and the compressive strength can reach up to 4.5MPa/cm2 after 28 days.