The invention discloses a separation method for a methanol-to-propylene (MTP) reaction product. According to the method, gas-phase feedstock and liquid-phase feedstock, which are obtained through subjecting the MTP reaction product to pretreatment and reaction product separator separation, sequentially enter a debutanizer and a deethanizer for treatment, treatment is carried out by a debutanizer refluxing tank top fractionating column debutanization and deethanizer refluxing tank top fractionating column deethanization combined process, and then, polymerization-grade propylene is obtained. According to the method, the product quality and recovery rate of the propylene can be effectively guaranteed, meanwhile, the debutanizer and the deethanizer have no need of being operated at low temperatures, and a fractionating system is energy-saving remarkably.