To alleviate the exhaustion of petrochemical resources and reduce their use in the polyurethane industry, biopolyols derived from dextrin and glycerol were prepared and used in rigid polyurethane foam (RPUF). Through simple and eco-friendly physical mixing, biopolyols with different dextrin contents were obtained, and the effects of different biopolyols on the foaming process, combustion behavior, mechanical properties and biodegradability were investigated. The apparent density of the RPUF ranged from 31.4 kg/m3 to 49.1 kg/m3. Compared with conventional foam, RPUF based on dextrin and glycerol had a higher normalized compressive strength and biodegradability. In addition, when the ratio of dextrin to glycerol in the biopolyol was 1/1, the self-extinguishing time of the foam was only 9 s, and the LOI value was 14.5 percent higher than that of conventional foam. These results demonstrated that dextrin-glycerol polyols can completely replace petrochemical polyols to prepare water-foamed RPUF with excellent comprehensive properties.