Abstract: Bioactivities of 9 herbicides and 7 admixtures against pink woodsorrel (Oxalis corymbosa DC. ) in city lawm, were systemically determined. The results indicated that metribuzin, atrazine, caoping-2, caoping-3, and glyphosate had high control effectiveness against pink woodsorrel. The control effects were 88.66% - 99. 10% in the 20th day after treatment. The LC50 of caoping-1 against pink woodsorrel was 106. 67 mg/L on the 7th day after treatment, which showed high activity of removing weeds, and safety to lawn grass. The glyphosate had better effect against pink woodsorrel, but the growth of lawn grass were also inhibited to varying degrees at the concentrations used in the experiment.