Thiasulfuron methyl is a selective herbicide after seedling, which is an inhibitor of branched chain amino acid synthesis. It can inhibit the biosynthesis of valine, leucine and isoleucine, prevent cell division and stop the growth of sensitive crops. It is mainly used to control broad-leaved weeds in wheat, barley, oats and corn fields, such as amaranth, Portulaca oleracea, Artemisia annua, shepherd's purse, pig's hair, pig's plague, Granna, ox hazel, etc.