Abstract: Using reclaimed water for greenbelt irrigation, which can extend the application scope of reclaimed water, and it’s also very important to relief crisis caused from the lack of water in the city. 2 kinds of familiar greenbelt plants in Shenzhen-Torenia fournieri and Duranta repens. were applied as studying objects, using addition the concentration of chloride, residual chlorine, total salt, suspensions and increasing or reducing pH value into reclaimed water to test the endurance of greenbelt plants, from using the method of constructing regression Logistic equation based on the relationship between the relative electric conductivity (REC) in the leaf and concentration (value), then the median-lethal concentration(LT₅₀)was determined, so as to determine the upper threshold value. And the result showed that the method of constructing regression Logistic equation based on REC and concentration (value), then determined the median-lethal concentration(LT₅₀)was resultant feasible and theoretically reasonable, the results showed were consistent with the phenomena of the test completely, thus the method also could be citied to study on adversity conditions of plant endured. The optimal quality indicators of reclaimed water from the median-lethal concentration(LT₅₀)gained from this method were chloride<531.48 mg/L, residual chlorine<2.59 mg/L, total salt<1 605.5 mg/L, suspensions<141.63 mg/L, pH value between 5.29 and 10.28 respectively. The test outcome extended the application scope of reclaimed water quality indexes practically, and there were guidance meaning to establish the criterion of reclaimed water quality in greenbelt irrigation.