[Background] Climate change and human activities have intensified the spatial-temporal distribution of water and soil resources, resulting in the laws of watershed runoff-producing and sediment yield more complex, thus the study of the relationship between runoff and sediment transport at individual rainstorm in the changing environment is of great importance. Six watersheds in the Ningxia Hui Autonomous Region (Yuanzhou, Hebao, Huangjiahe, Longde, Pengyang, and Xiazhai), located in the Loess Hilly and Gully Region, were selected as study targets. [Methods] The data of flood peak, the sediment peak, the flood volume and the sediment load were firstly calculated from the rainstorm data of Year 1984 -2014. The runoff erosion power, the Mann-Kendall trend test and the Pettitt change point test were then used to analyze the characteristics of these hydrological variables in the six typical watersheds.The runoff erosion power was applied to predict the sediment transport modulus. The Mann-Kendall test was mainly applied on the analysis of the trend of flood peak, sediment peak, flood volume and sediment load series, and the Pettitt test was used to analyze the jump year of these series. [Results] 1) All the flood peak, sediment peak, flood volume and sediment load series of the six typical watersheds in Ningxia presented significant decreasing trends, except for the Hebao watershed. 2) The change points of the flood peak, sediment peak, flood volume and sediment load were all around 1998 and 2003. 3) The relationship between runoff erosion power and sediment transport model was plotted using logarithmic coordinates, and the relationship was well fitted by the power function, indicating that the sediment concentration was predicted by the runoff erosion power. 4) The relationships between the runoff erosion power and the sediment transport modulus were quite different before the change-point and after the change-point. [Conclusions] In the same basin, the power parameter b of the power function in the two parallel hydrological stations are similar, but parameter b of two series-wound hydrological stations are of slightly larger difference. The power parameter b is also influenced by both climate change and human activities, b is 0.6 before the change-point, and it tends to be 0.85 after the change-point. The runoff erosion power is less than 1 after the change-point, thus the increase of parameter b indicate that the sediment transport modulus decrease under the same runoff erosion power. There are two reasons for the increase of the parameter b after the change-point. One is that climate change leads to the decrease of runoff, and the other reason is human activities have changed the underlying surface of the basin, making the sediment yield decreased more significantly. Therefore, the power parameters b of the rainstorm sediment transport model can be used as a reference index for soil and water conservation and the improvement of regional ecological environment of soil and water loss.