Abstract: To prevent severe pollution of inorganic snowmelting agents on greenery along urban roads, half lethal dose (LD50) of plant population was confirmed through stress simulation of chloride snowmelting agent on Euonymus japonicus, plant physiological change analysis, plant population lethality rate statistic and mathematic modeling analysis within a 30day subacute toxicity test. Results indicated that a significant positive correlation in the early stage and a significant negative correlation in the later stage were observed between the total content of chlorophyll a and b in plants and cumulative dose of chloride snowmelting agent. The free Lproline content in plants and the dose of snowmelting agent were positively correlated during the whole period. No significant correlation in the initial stage, but a significant negative correlation in the later stage was observed between the soluble protein and the dose of snowmelting agent. The LD50 of chloride snowmelting agent on E. japonicus is 5 kg/(L•m2) within a 30-day period.