Chemical weed control with effective and highly active herbicides has been very useful and convenient means. It has contributed to stable crop production and is labor saving. Recent herbicides have had characteristics such as high effectiveness without causing environmental pollution or harmful effects, and appropriate herbicides having high activity, low toxicity, high selectivity and being non-persistent have been developed. Trials were conducted to evaluate the paddy field utility of a premix of thenylchlor and bensulfuron-methyl. The treatments included the premix at two rates, and two standard treatments-butachlor and butachlor/bensulfuron-methyl. The experiments were conducted by Taichung, Kaohsiung and Taoyuan District Agricultural Research and Extension Stations to evaluate this chemical for rice crop tolerance and efficacy of weed control. Echinochloa crus-galli, Cyperus difformis, Monochoria vaginalis, and Lindernia cordiforia were controlled with high efficiency by applications of the premixture of thenylchlor plus bensulfuron-methyl with 0.3 and 0.35L/ha. This mixture at 0.3 and 0.35kg/ha was safe on tested rice cultivars. They can be applied at 7~8 days (1(superscript st) crop) or 5~6 days (2(superscript nd) crop) after rice transplanting and have to date proven very effective in the control of a wide range of annual and perennial broad leaf weeds, as well as sedges.