This trial was carried out to evaluate the nutritional values of sweet potato waste and manioc waste for growing Rex rabbits. Thirty white growing Rex rabbits at the age of 100 days with an average weight of (1.78±0.20) kg were divided into 3 groups with 5 replicates in each group and 2 rabbits per replicate. A basal diet was formulated to meet requirements for growing Rex rabbits and two trial diets were formulated by substituting 15% of the basal diet with sweet potato waste and manioc waste, respectively. Total fecal collection method was applied in the digestion test. Both pretrial and trial period was 5 days. The results showed as follows: 1) gross energy (GE) and the contents of dry matter (DM), crude protein (CP), crude fiber (CF), neutral detergent fiber(NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), ether extract (EE), ash, calcium (Ca), phosphorus (P) and nitrogen free extract (NFE) of sweet potato waste were 13.49 MJ/kg, 90.08%, 2.63%, 10.66%, 16.90%, 13.27%, 4.56%, 2.77%, 8.74%, 1.12% 0.17% and 65.29%, respectively, and those of manioc waste were 14.30 MJ/kg, 95.76%, 2.39%, 16.85%, 16.64%, 13.08%, 2.67%, 4.41%, 3.05%, 0.91%, 0.07% and 69.07%, respectively. 2) The apparent digestible energy of sweet potato waste and manioc waste were 11.47 and 13.06 MJ/kg, respectively . The apparent digestibility of GE, DM, CP, CF, NDF, ADF, EE, ash, Ca,P and NFE of sweet potato waste were 85.00%, 74.64%, 92.60%, 20.84%, 30.13%, 10.69%, 41.47%, 9.25%, 34.16%, 47.33%, 51.13% and 80.57%, respectively, and those of manioc waste were 91.36%, 89.92%, 88.94%, 58.08%, 30.09%, 5.39%, 27.02%, 7.24%, 84.27%, 70.30%, 27.43% and 96.25%, respectively. In conclusion, there are certain differences between the nutrient digestibility of sweet potato waste and manioc waste for growing Rex rabbits, and the values of manioc waste are better than those of sweet potato waste combined with the chemical analysis of feed ingredients.