To investigate the alkali resistance of the hybrid of Leuciscus and its parent Leuciscus waleckii (female parent) and Leuciscus idus (male parent) of the Irtysh River in Xinjiang, the alkalinity stress experiment of 50 mmol/L NaHCO₃ was carried out on three experimental fish for 7 days. Several physiological indexes and corresponding gene expressions involving osmotic pressure regulation and ammonia metabolism and significantly related to alkali resistance were compared and studied. The results showed that the Na⁺/K⁺ ATPase (NKA) activity and gene expression (ATPase α1-like and ATPase α3) of the gill tissues of the female parent with strong alkali resistance were higher than those of hybrids, and significantly higher than those of the male parent. The serum alkaline phosphatase (AKP) activity and the gene expression amount (alpl) of gill tissue were significantly lower than those of the other two fish, indicating that the female parent may regulate NKA enzyme activity through AKP dephosphorylation and participate in osmotic pressure regulation under high alkaline stress. The detection of ammonia metabolism related indexes showed that the blood ammonia (Amon) and urea nitrogen (BUN) contents of the female parent were extremely significantly lower than those of the other two fish, while the serum glutamate dehydrogenase (GDH) and glutamine synthetase (GS), as well as the expression of related genes in the gill tissue (glud, glul, Rhbg and Rhcg1) were mostly higher than those of hybrids, and significantly higher than those of the male parent, indicating that the female parent consumed ammonia in the body by synthesizing ammonia intermediate metabolites and increasing the activity of ammonia transporters. In summary, these physiological indexes were significantly related to the female parent's strong alkali resistance, and were well inherited to its hybrid offspring. The results of this study provide a theoretical basis for the comprehensive evaluation of the alkali resistance of fish, and lay a working foundation for the selection and breeding of new varieties of alkali resistance and the declaration of improved varieties of Leuciscus.