Abstract: The Chishui River, as a key section of the National Nature Reserve for Rare and Endemic Fishes in the upper Changjiang River, provides essential physical habitat conditions for fish spawning within its channels. To quantify the suitable flow velocity and water depth required for fish spawning and reproduction in the Chishui River, five typical spawning grounds were selected as research objects. Focusing on the hydrodynamic demands for fish spawning, in-situ observations of the hydrodynamic conditions in the spawning ground habitats were conducted, and the hydrodynamic characteristics of these spawning grounds were analyzed. The results show that fish spawning grounds are distributed in curved and braided river reaches with specific morphological features. The Froude number (Fr) of the spawning grounds ranges from 0 to 0.359, indicating subcritical flow in all cases. The maximum flow velocity in the spawning grounds is 1.93 m/s, and the maximum water depth is 18.27 m. Frequency distribution curves of flow velocity and water depth are constructed for the fish spawning grounds. The 25%~75% distribution interval is defined as the suitable hydrodynamic range for fish spawning, and suitability curves for flow velocity and water depth are developed accordingly. The suitable flow velocity range for fish spawning is determined to be 0.16~0.57 m/s, and the suitable water depth range is 2.68~9.74 m. The findings of this study can provide scientific support for reproductive habitat quality evaluation and the implementation of conservation measures in the Chishui River reserve.