The effect of exogenous phosphorus on the release of arsenic in the sediment of plateau lakeshore wetland deserves further study. The sediment samples in Yangzonghai Lakeshore Wetland which is located in Yunnan Province was selected as the research object, and the batch experiment method was carried out to monitor the release kinetics of arsenic. It was found that phosphorus input would facilitate the release of arsenic in the short period (less than 3 d), but the release would tend to be minimum after long period (30 d). After the input of phosphorus, the bioavailability of arsenic in the sediment would increase, whereas the sorption capacity for phosphorus decreased.