In order to study the influence of rainfall factors on runoff and erosion of fly ash (CFA), and reveal the law of runoff and sediment yield of CFA，runoff generation and erosion (RGE) characteristics of CFA were studied under natural rainfall conditions during the rainy season. This study was carried out by means of located observation methods to analysis natural rainfall events in experimental plots. The results showed that: (1) During the observation period，the total rainfall was 1 160.0 mm, while the erosive rainfall was 720.7 mm. The total rainfall and erosive rainfall in July were the most, being 409.6 mm and 217.1 mm, respectively. Heavy rains of erosive rainfall was 280.1 mm; (2) RGE in July was the greatest, being 0.72, 1.06, 0.67 m3, and 0.30, 0.90, 0.21 kg, respectively. RGE of rainstorm were biggest, respectively was 0.62, 1.02, 0.73 m3 and 0.16, 0.57, 0.15 kg. RGSE of the rainfall more than 50 mm were the biggest, being 0.79, 0.98, 0.53 m3, and 0.17, 0.72, 0.15 kg, respectively, RGE of the Rainfall intensity stronger than 40 mm/h were the biggest, being 0.82,1.06,0.76 m3, and 0.21,0.87, 0.19 kg, respectively; (3)Rainfall, I30, rainfall erosion force were associated with a significant yield in RGE. Rainfall capacity played a vital role in the runoff, rainfall erosion played a vital role in the sediment yield, while the relationship between RGE and rainfall duration was not significant. The relationships between RGE and rainfall capacity, and I30 implied by the equation were polynomial. The relationship between runoff and rainfall duration was linear, but there was no significant relationship between sediment yield and rainfall duration. RGE increased with the accumulation of rainfall characteristics, with erosive rainfall and rainfall erosion having particularly evident impact on RGE. The results are beneficial to the prevention and control of CFA loss in the storage yard, and can provide a reference for the ecological restoration of the CFA storage yard.