Abstract: ［Abstract］Obejective　To get the knowledge of the change tendency of arsenic pollution Yangzonghai Lake and its surrounding areas，and provide reliable evidences for the safety of drinking water in the local areas．Methods　Surveillance of the concentration of arsenic in Yangzonghai Lake and the surrounding areas was carried out from 2008 to 2011．The surveillance used the methods required in “Surveillance Design of Arsenic pollution in Yangzonghai Lake of Kunming City from 2008～2011”．Results　Totally 238 water samples were tested，the result of arsenic in the water sources of Liushuwan is in 0.021 6～0.128 mg/L，the highest concentration is 0.128 mg/L in Sep 2009，which is as 1.5 times higher as the standards requirement; the lowest concentration is 0.0216 mg/L in Mar．2011. The result of arsenic in the water sources of the first level pumping station in the Aluminum Factory of Cheng Gong County is among 0.029 5～0.126 mg/L， the highest is 0.126 mg/L in Sep．2009，the lowest is 0.029 5 mg/L in Mar．2011．Conclusions　The overall arsenic concentration level in Yangzonghai Lake and its surrounding areas has a decreasing trend．Up to Mar．2011，the arsenic content in the surveillance places has meet the requirement of the standard of on-the ground water for category Ⅲ.