The invention discloses a material used for preparing a rigid foamed plastic, and a preparation method of the rigid foamed plastic. According to the preparation method, a polyester polyol, an isocyanate, a catalyst 1, a catalyst 2, a physical foaming agent, a foam stabilizer, and a cross-linking agent are taken as raw materials; the degree of functionality of the polyester polyol is high, and ranges from 2.8 to 3.0, the viscosity of the polyester polyol at 25 DEG C ranges from 7000 to 10000mPa.S, hydroxyl value ranges from 380 to 450mgKOH/g, and acid value ranges from 0.1 to 2mgKOH/g; the foam stabilizer is a mixture of two organosilicon surfactants; organic combination of two key technologies, high efficiency emulsifying and nucleation, in rigid foamed plastic processing is realized, and the rigid foamed plastic with a compression strength and a bending strength of 500KPa or higher, and a dimension changing rate (80 DEG C, 48h) of 0.4% or lower is prepared. The rigid foamed plastic can be widely applied to the fields such as building and building material, communication and transportation, and refrigerating plants such as refrigerators, and cold storages.