In order to explore the effects of sea buckthorn (Hippophae rhamnoides) powder on growth, antioxidant ability and non-specific immunity of Yellow River carp (Cyprinus carpio haematopterus), a total of 450 C. carpio haematopterus with similar body weight about 7.55 g were randomly divided into five groups: control, HG, G-LSP, G-MSP, G-HSP, respectively. A 10-week feeding trial was performed. The results indicated that the weight gain rate of C. carpio haematopterus in G-HSP group was significantly higher than that in HG group. Compared with the control group, the content of malondialdehyde (MDA) in serum and hepatopancreas increased, but the activity of (CAT), superoxide dismutase (SOD) and total antioxidant activity (T-AOC) in serum and hepatopancreas decreased. These negative effects could be relieved with sea buckthorn powder supplementation. The high-carbohydrate diet inhibited nrf2 mRNA levels of hepatopancreas and muscle, while the mRNA levels of keap1 were promoted. Sea buckthorn powder significantly inhibited the decrease of nrf2 mRNA levels and increase of keap1 mRNA levels induced by the HG diet. And the antioxidant-related genes (gr, cat, gpx and sod) mRNA levels were also promoted by sea buckthorn powder. Moreover, fish fed the diet containing 0.5% sea buckthorn powder had higher activity of alkaline phosphatase (AKP), acid phosphatase (ACP), lysozyme (LZM) and the content of albumin (Alb) in serum, spleen and intestine. In addition, sea buckthorn powder can restore the abnormal mRNA expression of nf-κb, il-1β and tnf-α in spleen and intestine caused by high-carbohydrate diet. In conclusion, sea buckthorn powder can alleviate oxidative stress and inflammation injury caused by high-carbohydrate diet, and improve the growth performance, and enhance antioxidant ability and non-specific immunity of C. carpio haematopterus. The recommended dosage of sea buckthorn powder in diet is 0.5%.