Through hydroponics experiment of Juncus effusus, Lythrum salicaria, Acorus calamus and Pontederia cordata with urban runoff, the paper studied the purification efficiency of wetland plant for main pollutants of urban runoff, such as COD, TN, TP and heavy metal and analyzed the tolerance and adaptability of the plants on runoff pollutants. The results showed that the purification efficiency of the plants for heavy metal is satisfactory. The tolerance and removal rate of Lythrum salicaria on COD are quite low, the plant will lead to death when COD concentration is beyond 1160 mg/L. Juncus effusus has poor adaptability to pH, therefore, the acid rain might exert a severe effect on the treatment efficiency and growth of Juncus effusus. The treatment capacity of Acorus calamus and Pontederia cordata on runoff TP is almost the same when pH values is below 6. When TN in the runoff is less than 20 mg/L, the TN removal efficiency of Acorus calamus is higher than 93 % and better than that of Pontederia cordata. The COD removal efficiency and adaptability of Acorus calamus are also better than those of other three alternatives. So,Acorus calamus is a suitable wetland plant for urban runoff.