Abstract:The allelopathy effect of aqueous extracts from Trifolium repens L. on root tip cells of Vicia faba under different temperature (5℃,25℃ and 35℃) stresses was investigated by using micronucleus assay and chromosome aberration assay. The results indicated that the mitotic index of V.faba root tip cells treated by low concentration of aqueous extracts increased and it decreased at high concentration, the aqueous extracts of T.repens also caused various types of chromosome aberrations such as micronucleus, chromosome fragment, chromosomal bridge and lagging chromosome,and micronucleus and aberration rates increased along with concentration of extracts. This research showed the allelopathy effects of aqueous extracts from T.repens by different temperature treatments were different, the low temperature group (5℃) was the strongest, high temperature group (35℃) was second, normal temperature（25℃）was the smallest, which was probably due to temperature stress changed and increased the secondary metabolites of T.repens, increased genetic toxicity of the aqueous extracts of this plant.