Recently, Concern of non-point pollutant was increased that depending on the development of point source reduction policy. Non-point pollutant was not easy to monitoring and treatment without professional experience in fields. Runoff characteristic of non-point pollutant has various pattern cause of several parameters such as rainfall, rainfall intensity and antecedent dry days(ADD) etc. For this reason, Studies of reducing non-point pollutant using constructed wetland(CW) has attracted attention. In this study, It was investigated about inflow characteristics of BOD, SS, TN and TP by total of 20 monitoring, and It was used to considered the relationship of reduction rate and loads by statistically analyzed. The reduction efficiency of the CW was calculated by Effect mean concentration (EMC). It was used to determined the main effect parameters using a correlation of each parameter. The results of correlation analysis, It was observed that EMC of BOD and COD were significantly affected by rainfall. The reduction facilities of non-point pollutant need more various studies for characteristics of each facilities by significantly parameter.