Abstract: In order to achieve the ecological balance, the influence mechanism of mixed culture of Carassius auratus average weight of (48.53±2.11) g on the growth and nutritional composition of Eriocheir sinensis average weight of (23.48±0.82) g were selected as the research objects in this paper. The density of C. auratus was set at 0 fish/667 m² (T0, control), 100 fish/667 m² (T1), 200 fish/667 m² (T2), and 300 fish/667 m² (T3) in mixed culture with E. sinensis. The experimental period lasted for 90d. The results showed that the final body weight, weight gain rate, specific growth rate, meat yield, hepatopancreas index, gonadal index, and total edible rate were higher in the T1 in 4 experimental groups, while the feed conversion ratio was significantly lower than that in the other groups (P<0.05). The total amino acid content, essential amino acid content, and essential amino acid score in T2 muscle were the highest, with Thr, Leu, Phe, and Lys levels in T2 muscle exceeding significantly in other groups (P<0.05). Research demonstrated that a stocking density of 100—200 fish/667 m² of C. auratus not only enhanced the growth of E. sinensis but also optimized the edible tissues and nutrient quality of E. sinensis muscle.