In order to know the water quality of Danshuei River, this study collects data from 12 monitoring stations set by Environmental Protection Administration (EPA) in the upper, middle, and lower reaches of Danshuei River out of 38 stations in the River basin during 2002 to 2016 to do parameter statistics and analysis. There are 18 monitoring items. EPA executes monitoring practice quarterly. The analysis shows that, Fuchou Bridge (l) station and Ciulan Bridge (h) station possess the most monitoring items whose failure rate is over 50%. This shows that, in Danshuei River environment, EPA should take countermeasure of improving water quality especially in low reach of Dahan River and middle reach of Sindian River, extend improvement measures, and enhance laws and regulations force, so as to reduce the failure rate in Danshuei River basin year by year. For the concentration of 5 parameters: Total Phosphate(TP), Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), Suspended Solids (SS), and Ammonia Nitrogen (NH3-N) monitored among the unqualified stations that over 50% of their monitoring results fail to meet the water quality standards, 4 stations do not meet TP standard value, 3 stations do not meet NH3-N standard value, 2 stations do not meet DO standard value, 1 station does not meet BOD standard value, and 1 station does not meet SS standard value. Over the years, none of the monitoring values in these stations meets Surface Water Classification and Water Quality Standards regulated by EPA. The failure rate and time of measurement results of the stations mentioned above are briefly summarized as following. For TP, Ciulan Bridge (h) station has the highest failure rate, 91.67%, and its TP value exceeds the B Class of Environmental Quality Standards for River for 55 times. For NH3-N, Jiangpei Bridge (c) station and Fuchou Bridge (l) station have the highest failure rate, 100%, and their NH3-N value exceeds the C Class of Environmental Quality Standards for River for 60 times. For DO, Fuchou Bridge (l) station has the highest failure rate, 76.67%, and its DO value exceeds the C Class of Environmental Quality Standards for River for 46 times. As for BOD and SS, Fuchou Bridge (l) station and Ciulan Bridge (h) station have the failure rate, 83.33% and 60% respectively, and their BOD and SS values exceed the C Class of Environmental Quality Standards for River for 50 times and the B Class of Environmental Quality Standards for River for 36 times. In addition, for heavy metal items, few stations fail to meet the standard for over 50% times of measurement results. Only Copper (Cu) value in Fuchou Bridge (l) station has the failure rate 58.33% and 35 times that its value exceeds EPA standards.