Rice allelopathy is implemented through its release of allelochemicals to environment. Many researchers considered that rice allelochemicals were phenolics. The action mechanisms of rice against weeds allelochemicals included the inhibition of seed germination and emergence, the effect on the balance of hormones, the damage on the integrity of cell membrane systems, the effect on photosynthesis and respiration, the disturbance of nutrient and water uptake and the effect on the protein synthesis and gene expression. Rice allelopathy is controlled by polygenes, and inherited quantitatively. Several QTLs were identified by the methods of molecular biological techniques and allelopathic bioassay. It might be the important research work to locate the QTLs accurately and to clone the allelopathic genes with the method of marker-assisted selection and the near isogenic lines.