Three trials were carried out by Hualien, Taoyuan and Tainan District Agricultural Research and Extension Stations to evaluate the new sulfonylurea herbicide flazasulfuron for the control of weeds in non-crop land by post-emergence application. Spraying 150 and 300 g/ha flazasulfuron provided an effective control of annual and perennial weeds such as Kyllinga brevifolia, Portulaca oleracea, Ageratum conyzoides, Tridax procumbens, Amaranthus viridis, Desmodium triflorum, Oxalis corniculata, Alysicarpus vaginalis, Hydrocotyle sibthorpioides. But averaged over all field trials at 40 days after application, grasses control with flazasulfuron atl50 and 300 g/ha was less than 45%.