The hydrological conditions in the Three Gorges Reservoir impact the spawning of four major Chinese carps in the Yangtze River. Proper flow, water level, sediment concentration, water rise, and temperature are crucial for successful spawning. After the reservoir's impoundment, sediment concentration has the most significant effect on carp larvae abundance. The decline in flow, water level, and temperature delays spawning, affecting the scale and composition of carp populations. Silver carp become more dominant post-impoundment. This study helps in protecting these important fish species in the Three Gorges Reservoir.