Abstract: Erosion processes on engineering deposits of construction projects are different from those in farmland and fallow land due to their loose accumulation, coarse texture, complex composition, and steep slope. For this reason, such erosion is often considered typical of artificially-accelerated types. We have developed physical models for the deposited bodies with different slopes and different gravel contents based on field surveys on a large number of engineering deposits, focusing on the impacts of gravel content on runoff velocity and sediment yield in the condition of simulated rainfall. Results show that 1) flow velocity increases rapidly in the initial 3 min rainfall and then tends to be relatively stable. At slopes less than 25°, flow velocity on the slope of a deposited body that contains gravels is lower than that on a pure soil slope because gravels enhance the curvature of flow path and hence reduce flow velocity. A power function can fit well the relation of average stable velocity versus rainfall intensity and gravel content, while a binary linear relation fits better for slopes greater than 25°. 2) Sediment-yielding rate shows a decreasing volatility in the initial 12 min runoff and then tends to be stabilized, with its initial value 1.7 ~ 3.1 times greater than the stable stage. In each rainfall test, a peak of sediment yield was observed after 3 min runoff. An increase in rainfall intensity from 1.0 to 1.5 mm/min leads to an increase of 82.7% ~ 117.3% in the average yielding rate. There exists a threshold slope of about 25° that maximizes the yielding rate up to a peak 1.3 ~ 1.7 times those at other slopes. At the initial and stable stages, the yielding rate on pure soil slope was 0.6% ~ 28.7% greater than gravels-containing slope. 3) Average sediment yielding rate shows significant correlation with flow velocity in the entire erosion process including the initial and stable stages. The amount of erosion increases by 74.0% ~ 95.9% as rainfall intensity increases by 50%, and the erosion on pure soil slope is always greater than the corresponding gravels-containing slope erosion. Generally, the erosion in the initial 12 min runoff contributes 38.3% ~ 50.7% to the total erosion in the entire process. Thus, to control soil and water loss from the engineering deposits, a particular emphasis should be laid on those conservation measures that are effective at the initial stage of rainfall or runoff.