Abstract: Information on the animal biodiversity in organic paddy fields is poorly understood and surprisingly obscure in China. A comparative filed study on the diversity and composition of animal community in 7-year, 9-year and 11-year organic and conventional rice fields was conducted. Animals observed via multiple field surveys belonged to Gastropoda, Oligocllaeta, Hirudinea, Insecta, Malacostraca, Branchiopoda, Arachnoidea, Amphibia, Pisces, and Mammalia (including 10 classes, 28 orders, 130 species) in organic paddy field. However, the animals observed in conventional paddy field belonged to only 8 classes, 13 orders, 27 species. Arthropods were the dominant species in all observed animal community. All observed arthropods belong to 4 classes, 15 orders, and 106 species (81.5% of total observed animal species) while other animals contained 6 classes, 13 orders, 24 species were identified in the organic paddy fields (18.5% of total observed animal species). Nevertheless, only 3 classes, 9 orders, 22 species (81.5% of total observed animal species) for arthropods whereas 5 classes, 4 orders, 5 species (18.5% of total observed animal species) for other animals were identified in the conventional paddy fields. The Margalef diversity and Pielou's evenness index of fishes, amphibians and arthropods were significantly (P < 0.01) higher in organic farms than that in conventional ones. Simpson diversity index of annelids, fishes and amphibians were significantly (P < 0.01) higher in the organic paddy fields than that in the conventional paddy fields. The results indicate that the aquatic ecosystem of organic paddy cultivation has higher ecological stability and environmental quality.