NOVELTY - Preparing isooctanol polyoxypropylene ether succinic acid diester sodium sulfonate, involves: adding epoxypropane to isooctanol, in presence of modified double metal cyanide (DMC) catalyst, to perform condensation reaction, so as to obtain the isooctanol polyoxypropylene ether; esterifying with the maleic anhydride in presence of the solid super acid peroxodisulfate/zirconium oxide as catalyst; sulfonating with the sodium pyrosulfite solution in presence of phase transfer catalyst, then adding sodium hydroxide (NaOH) aqueous solution until the reactant pH is 4-7.    USE - For preparing isooctanol polyoxypropylene ether succinic acid diester sodium sulfonate (claimed) used as emulsifier, dispersant and stabilizing agent in petroleum chemical industry, as pesticide, as medicine, in metallurgy, textile, printing and dyeing, paper making, tanning industry, or in textile industry.    ADVANTAGE - The process is clean, environmental friendly and simple, which has stronger permeability and reduces foam in the production process. The process adopts solid catalyst, does not need neutralizing. The improved DMC catalyst is high performance polyether catalyst, compared with the traditional alkali catalyst (KOH), it has high activity, little dosage, short reaction time, does not need post-processing, can greatly reduce energy consumption and material consumption. The method reduces side reaction, simplifies the processing technique, no pollution, no corrosion and reduces production cost.    DETAILED DESCRIPTION - Preparing isooctanol polyoxypropylene ether succinic acid diester sodium sulfonate, involves: adding epoxypropane to isooctanol, in presence of modified double metal cyanide (DMC) catalyst, to perform condensation reaction, so as to obtain the isooctanol polyoxypropylene ether; esterifying with the maleic anhydride in presence of the solid super acid peroxodisulfate (S2O8(2-))/zirconium oxide (ZrO2) as catalyst; sulfonating with the sodium pyrosulfite solution in presence of phase transfer catalyst, then adding sodium hydroxide (NaOH) aqueous solution until the reactant pH is 4-7, so that the isooctanol polyoxypropylene ether succinic acid diester sodium sulfonate is obtained, where the mole ratio of the isooctanol and epoxypropane is 1 to 1-4; the mole ratio of the isooctanol polyoxypropylene ether and the maleic anhydride is 30-2-1; the mole ratio of the pyrosulfite and the isooctanol polyoxypropylene ether succinic acid diester is 0.9-1.2 to 2. The temperature of the condensation reaction is 70-150 degrees C and the reaction time is 1-3 hours; the temperature of esterification reaction is 90-160 degrees C and the reaction time is 2-6 hours.