This experiment was conducted to study the effects of soybean oil supplemental level on growth performance, digestion and metabolism of nutrients, serum biochemical indices and fur quality of weaner to 3-month-old Rex rabbits. Two hundred weaner Rex rabbits with similar body weight were randomly divided into 5 groups with 40 replicates per group and 1 rabbit per replicate. Rabbits in control group were fed a basal diet, and rabbits in other 4 groups were fed experimental diets which were formulated with 1%, 2%, 3% and 4% corn replacement by soybean oil with the same proportion on basal diet. The duration of the preliminary experiment was 7 days and the duration of the formal experiment was 53 days. The results showed as follows: soybean oil supplementation significantly reduced the average daily feed intake (P<0.01), but had no significant effect on average daily gain (P>0.05) under the condition of no significant difference in the initial body weight (P>0.05). The feed/gain in 3% group was the lowest and significantly lower than that in control group (P<0.01), but had no significant difference compared with other supplemental groups (P>0.05). Soybean oil supplementation significantly reduced the gross energy intake, nitrogen intake and fecal nitrogen (P<0.05 or P<0.01), but had no significant effects on fecal energy, urine energy, digestible nitrogen, nitrogen retention and nitrogen utilization rate (P>0.05). The energy digestibility and metabolizability in all supplemental groups were higher than those in control group, but no significant differences were found (P>0.05). The nitrogen apparent digestibility was firstly increased and then decreased with the increase of soybean oil supplemental level, and reached the maximum when supplemental level was 2%. The nitrogen apparent digestibility in 2% group was significantly higher than that in control group (P<0.05), but had no significant difference compared with other supplemental groups (P>0.05). Soybean oil supplemental level significantly affected serum low density lipoprotein cholesterol content (P<0.01), but did not affect serum triglyceride, total cholesterol and high density lipoprotein cholesterol contents (P>0.05). Compared with the control group, the serum low density lipoprotein cholesterol content in all supplemental groups was significantly increased (P<0.01), but there were no significant differences among all supplemental groups (P>0.05). Soybean oil supplemental level did not affect fur area and weight (P>0.05), but the fibroblast growth factor 5 (FGF5) mRNA expression was significantly changed (P<0.01) and reached the maximum when supplemental level was 2%. Based on above results, the appropriate soybean oil supplemental level is 2% to 3% for weaner to 3-month-old Rex rabbits.