Preparation method of macromonomer for polymer polyol

The invention relates to a preparation method of a macromonomer for polymer polyol. The method comprises the following steps: adding a compound containing unsaturated double bonds, a catalyst and water into a reaction kettle, replacing air in the reaction kettle with nitrogen, and carrying out a stirring reaction at 10-30 DEG C for 2-3 hours; adding polyether polyol into the kettle, and reacting for 3-5 hours under the conditions that the temperature is 50-60 DEG C and the pressure is 0.02-0.5 MPa; heating to 100-130 DEG C, reacting for 5-8 hours under the pressure of 0.02-0.5 MPa, and vacuumizing to remove for 2-3 hours; keeping the reaction temperature at 100-130 DEG C, adding ethylene oxide into the kettle under micro-positive pressure of the system, and reacting for 3-5 hours; raising the temperature to 140 to 170 DEG C and reacting for 5 to 6 hours under the pressure of 0.02 to 0.5 MPa; and after the reaction is finished, cooling to below 80 DEG C to obtain the macromonomer product for the polymer polyol