Abstract: High-flow pulse is a key eco-hydrological indicator for the spawning of the drift egg-laying fish． To promote spawning of rare and unique fish species in the National Nature Reserve for Rare and Endemic Fishes in the upper reaches of the Yangtze River, and to explore conditions for ecological operation of cascade reservoirs in the lower Jinsha River, composition of runoff in the National Nature Reserve during drifting egg fish spawning was analyzed． Contribution ratio of upstream main and tributary streams to formation of high-flow pulses in National Nature Reserve was evaluated． The close relationship between spawning situation of Coreius and Leptobotia elongate and high-flow pulse of main and tributary streams was analyzed． Half of high-flow pulses are found formed by the joint flow rise of tributary streams and Jinsha River, whereas the other half are formed alone by the flow rise of tributary streams． The contribution ratio of the tributary streams to the formation of high-flow pulses is as high as 87.62%． The spawning of representative fish species mostly occurs during the period when high-flow pulses appear in tributary streams． The flow rise in tributary streams is found to play a key role in the formation of high-flow pulses． Ecological compensation operations should be carried out for the cascade reservoirs in the lower Jinsha River, in conjunction with flow-rises in tributary streams． This will be beneficial for fish spawning and reproduction in the National Nature Reserve, and for reduced artificial flood peak pressure of the cascade reservoirs in the lower Jinsha River．