General comments:

Climate change may cause more intense rainfall, potentially increasing extreme flood events. Improving the flood forecasting accuracy is still a challenging and important task. This research coupled the weather research and forecasting (WRF) model with the fully-distributed WRF-Hydro and a semi-distributed Hydrological Engineering Center-Hydrological Modeling System (HEC-HMS) modeling system to improve the accuracy of flood simulation, and the lumped HEC-HMS model was also adopted using the observed gauge precipitation as a benchmark to test the model uncertainty. The error in the simulated WRF output rainfall was analyzed as one of the main source of errors. This research is interesting and shows an important reference value for researchers who aim to improve flood forecasting using the WRF products.

The manuscript follows a logical order and is generally well-written. I put forward some minor revision suggestions and comments for the authors to consider. I hope that the authors can deal with the comments seriously and make detailed revisions through more in-depth analysis.

Specific comments:

Point 1: Line 446-447. The manuscript mentions that the coupled WRF/HEC-HMS model simplifies hydrological processes for storm events 2 and 4. Could the authors elaborate on the underlying reasons for this limitation?

Point 2: Line 471-475. The manuscript suggests several recommendations for enhancing rainfall simulation, such as using observed rainfall for correction and integrating radar data assimilation. I suggest the authors add citations of research where these recommendations have been validated or tested.

Point 3: Line 17 and 83.  “simi-distributed” should be corrected to “semi-distributed”.

Point 4: Line 120. “Daqing River basin” should be capitalized as “Daqing River Basin” since it is a proper noun.

Point 5: Line 122. “Fuping (2219km2)” and “Zijingguan (1760km2)” should have spaces between the numbers and the unit “km²”.

Point 6: Line 125.  “Zijigguan” should be corrected to “Zijingguan”.

Point 7: Line 138. “events happened” can be changed to “events occurred”.

Point 8: Line 168. “Figure 2, subfigure for Event 2” is non-uniform compared to the others and should be replaced.

Point 9: Line 185. “WRf” should be corrected to “WRF”.

Point 10: Line 189. “sub-watershed” should be corrected to “sub-catchment” for consistency with previous terminology in the manuscript.

Point 11: Line 191. “50hPa top-layer pressure” should have spaces between the number and the unit “hPa” for clarity.

Point 12: Line 256. “Hydrologic” should be "Hydrological” for consistency.

Point 13: Line 266. “Metrologic data” should be corrected to "Meteorologic data”

Point 14: Line 371 and 394. “storm Event” should be capitalized as “Storm Event”.

Point 15: Line 404. “as shown in Table 2, has a better simulation result”. This phrase seems to be incorrectly placed, disrupting the flow of the sentence, and should be corrected as “(as shown in Table 2), has a better simulation result”.

Point 16: Line 440. “perform” should be “performs”.

Point 17: Line 482. “simi-distributed” should be “semi-distributed”.

Point 18: Line 484. “is carried out” should be “are carried out”.

Point 19: Line 490. “process" should be “processes”.