Abstract: The study aim was to explore the optimal dose and application time of pinoxaden in the control of Phalaris arundinacea in barley field. In the plot experiments, four doses (from 900 to 2400 mL/hm2) of pinoxaden (50 g/L) EC was applied for the control of P. arundinacea in barley field. The optimal application time of pinoxaden was 3- 4 leaf stage of P. arundinacea and 4- 5 leaf stage of barley. In this stage of P. arundinacea, the control efficacy of four doses was all more than 97% . The 50 g/L pinoxaden exhibited excellent efficacy to P. arundinacea, and the efficacy was better than that of the 69 g/L fenoxaprop-p-ethyl and manual weeding. In 4-5 leaf stage of barley and 3-4 leaf stage of P. arundinacea, when the pinoxaden was applied at the dose from 900 to 1200 mL/hm2, the efficacy for controlling P. arundinacea could be more than 97%. There was no harmful effect to other arthropods in field, and it was safe to barley.