To reveal the impacts of changes in flow and sediment on channel erosion and deposition in the lower Yellow River channel and to improve the efficiency of engineering regulation of flow and sediment for de-siltation, the formula for channel erosion and deposition in the lower reach by Chien Ning et al. was revised using flow and sediment data based on the “more incoming, more discharging” sediment transport characteristic of the Yellow River and the river sediment transport theory. Consequently, an erosion and deposition formula and a comprehensive incoming sediment coefficient with a clear physical meaning, which could more comprehensively reflect the effects of conditions such as flow and sediment volume and suspended sediment gradation, were obtained. The results show that the revised formula has a unified parameter and coefficient, and the simulated erosion and deposition intensities in both the full period and individual sub-periods have high accuracy; furthermore, it can be used to study the comprehensive flow-sediment relationship and erosion and deposition regulation mode in the lower Yellow River after reservoir sediment trapping and sediment gradation alteration; altering sediment gradation through reservoir sediment trapping and regulation can significantly affect the sediment transport capacity of the downstream channel; the optimal operation of “trapping coarse sediment and discharging fine sediment” for flood control and de-siltation reservoirs can largely reduce the deposition in the downstream channel, which is of great significance for maintaining the long-term stability of the downstream channel and ensuring the flood control capacity of the reservoirs.