Based on the CMORPH-Gauge merged data and observed rain gauge data, the daily area rainfall of 15 sub-catchments in the Huaihe River Basin was calculated during flood seasons(June to September)from 2008 to 2011, using the Thiessen polygon method and the grid arithmetic average method. Comparative statistical analysis was conducted on the results of the two methods. The results show that the two sets of area rainfall of the 15 sub-catchments exhibited systematic differences and a significant linear correlation. The daily area rainfall also showed systematic difference. The area rainfall based on rain gauge data was generally greater than that based on the CMORPH-Gauge merged data. There was a strong correspondence for the magnitude between the two sets of area rainfall. The overall correspondence ratio was 78. 8%, with the ratio of rainfall values that differed by an order of magnitude being 20. 5%. The correspondence ratio for the light-rainfall magnitude reached 91. 4%.