Headcut erosion has been the chief cause in reducing soil fertility and harming ecological environment and long-term serious headcut erosion has caused serious consequence to security of Dongzhi tableland. A simulated rainfall combined runoff scouring experiment was carried out to identify the headcut erosion process and pore water pressure variation on Dongzhi tableland of China. The plot was composed of upstream catchment area, gully head and downstream gully bed. The slope gradient of upstream catchment area (1.5 m×5 m) was 1°, 3°, 5° and 7°. The vertical height of gully head was 0.9 m. Besides, the slope gradient of downstream gully bed (1.5 m×1 m) was 1°, 3°, 5° and 7° which was consistent with the upstream catchment area. The constant-intensity rainfall simulator consisting of nozzles spaced 0.67 m apart, and the pure water was pumped to these nozzles, with the raindrop height of 2.05 m. The pore water pressure gauges were installed in the middle of plot, and the distance between pore water pressure gauges and gully head was 30, 60 and 100 cm with the depth was 30 and 60 cm, respectively. The results showed that the frequency of collapse increased with experimental time, which accounted for 27.48% of total amount when the experiment conducted over 150-180 min. The sediment discharge exhibited a decreased logarithmic relationship with experiment time. The sediment yield was 325.66-454.13, 471.13-787.71, 737.34-1 044.18, and 1 073.16-1 533.60 kg, respectively, under different slope gradient of 1°, 3°, 5° and 7°. There was a general tendency that sediment yield increased with increasing flow discharge and slope gradient. By multiple regression analysis, the sediment yield was found to be linearly related with slope gradient and flow discharges. The sediment yield rate increased 34.12%-97.48%, 22.75%-166.48%, 48.36%-324.59%, and 36.55%-131.76%, respectively, under 1°, 3°, 5°, and 7°. Compared to collapse time, the mutant site in sediment yield rate was delayed due to the deposit of sediment. Pore water pressure decreased with the increase in duration of runoff, and there was a significant linear or logarithmic relationship between pore water pressure and duration of test. The increase of pore water pressure was one of the key factors affecting the occurrence of collapse. When the slope gradient was 1° and the flow discharge was 3.0 m3/h, the pore water pressure was 0.86-1.29, 0.72-1.39, 1.00-1.28, 0.52-1.47, 0.67-1.35 and 0.62-1.19 kPa, respectively, of probe 1 to 6 as the tests time was 12 min, and pore water pressure decreased with buried depth. In addition, the pore water pressure at 30 cm was greater than 60 cm due to the decrease of soil infiltration. These findings hold important implications for the eco-recovery of the gully region of Loess Plateau. Study on erosion process and pore water pressure characteristics of Dongzhi tableland can further reveal the mechanism, lay an important foundation for the research on the model of gully erosion process, and provide important information for realization of land resources of Dongzhi tableland in the Loess Plateau.