By using specific secondary metabolites as markers, this paper determined the allelopathic indices of nine allelopathic rice varieties widely cultivated in South China, and evaluated the main agronomic characters of these varieties and their weed-inhibiting effects in field. The correlations among allelopathic indices, agronomic characters and weed-inhibiting effects of test rice varieties were also analyzed. The results indicated that not all the rice varieties demonstrated their weed-inhibiting effects in field, and there were no relationships between allelopathic traits and main agronomic characters. However, the rice varieties with both allelopathic traits and competitive agronomic characters could significantly inhibit the weeds in field. The non-correlation between allelopathic traits and main agronomic characters of test rice varieties suggested that the transfer of allelopathic traits into rice varieties did not affect their agronomic characters, i.e., it's possible to breed allelopathic rice cultivars with any agronomic characters.