Abstract: The research progress on the mechanism of chemicals inhibiting acetolactate synthase (ALS),including the target of inhibitors,selective mechanism,phytotoxicity mechanism,and gametocidal activity on cruciferous plants was summarized.ALS is the target of several herbicides,including sulfonylurea,imidazolinone,sulfonylamino-carbonyltriazolinone,triazolopyrimidine and pyrimidinylthio (or oxy)-benzoates.Recently,some ALS inhibiting-herbicides such as tribenuron-methyl and amidosulfuron were highlighted by their gametocidal activity on susceptible plant.However,the mechanism leading to phytotoxicity of ALS inhibitors is not understood.Some possible mechanisms including branched-amino acid starvation,repression of DNA synthesis,accumulation of ALS substrate,inhibition of photoassimilate translocation,anaerobic respiration etc.were hypothesized but no one was validated.In order to reveal new clues for study the phytotoxicity mechanism,more physiological and biochemical events in response to application of ALS inhibitors need to be discovered by using high-throughput analytical methods including metabolomics,transcriptomics,and proteomics.