Firstly, the hydrological and meteorological features of the upper reaches of the YellowRiver above Tanguag are analyzed based on observation data, and effects of EI Nino and La Ninaevents on the high and low flow in the upper Yellow River are discussed. The results show El Ninoand La Nina events possess consanguineous relationship with runoff in the upper Yellow River. As awhole, the probability of low flow occurrence in the upper Yellow River is relatively great alongwith the occurrence of El Nino event. Moreover, the flood in the upper Yellow River occursfrequently with the occurrence of La Nina event. Besides, the results also show dissimilarity of ElNino event occurring time exerts greater impact on high flow and low flow in the upper YellowRiver, that is, the probability of drought will be greater in the same year if El Nino event occurs inspring, the high-flow may happen in this year if El Nino occurs in summer or autumn; the longer thecontinuous period of El Nino is, the lower the runoff in the upper Yellow River is.