Lake Xingkai is a boundary lake between China and Russia.Based on monitoring and statistical data in the Big Lake Xingkai, the average value of COD_Mn was 5.42mg/L, B0D₅ was 1.59-2.91 mg/L, TP was 0.35mg/L during the 1994-1998 period, which was meso-eutrophic lake.Based on the monitoring report in the Big Lake Xingkai in 2009, the average value of C0D_Mn was 4.09mg/L, the average of NH₄-N was 0.466mg/L.The water quality standard decreased from Grade Ⅱ to Grade Ⅲ and was further degraded.During the 2005-2009 period based on monitoring data from Astrakhanka of Russia, the major pollution was organic pollutants, in which COD_Mn was 11.5-16.2mg/L and TP was 0.046-0.266mg/L.The results indicated that water quality was deteriorated and had eutrophication tendency.The industrial and tourism sewage seriously influenced on water environment, and the water environment safety faces certain pressures.This article analyzed the threats and provided the feasibility countermeasures for protecting waters of Lake Xingkai.