To study the complex hydraulic characteristics of the surge chamber with partition-type bifurcation pipe in bottom, a three-dimensional numerical model is built to analyze the local water flow patterns under typical flow regimes, the relationship of local head loss coefficient and split ratio under split/combined flow state, the head loss coefficient of flow through the bottom of surge chamber under normal operation state and the head loss characteristics. Moreover, a conversion formula is derived between the head loss coefficient and the flow coefficient when all water flows into/out of the surge chamber. Based on the analysis, the local hydraulic characteristics of surge chamber with partition-type bifurcated pipe in bottom are completely clarified. The results show that, the numerical simulation method can accurately reveal the hydraulic characteristics of the given surge chamber and the computed flow coefficient flowing into/out of the surge chamber is mostly between 0. 6 and 0. 8, which is relatively larger than the code.