In this study, the organic mercapto polymer chelating agent (DDTC), Na₂S and NaOH were selected as the capturing agent and used to remove complex Ni deeply from the electroplating plant wastewater. It paid the key focus on the study of reaction pH, pharmaceutical dosage, reaction time and other factors that could influence the removal of Ni. Besides, the mechanisms of Ni²⁺ removing by Na₂S-DDTC was also discussed. The results showed that Na₂S-DDTC had a high efficiency under the following conditions: ρ(Ni)=300mg/L of initial nickel concentration, pH 9.0, Na₂S and DDTC dosing ratio was ρ(Na₂S)/ρ(DDTC)=10, where ρ(Na₂S)=600mg/L, ρ(DDTC)=60mg/L, the reaction time t=6.0min, the dosage of PAM was 1.0mg/L, leading to 0.064mg/L of residual Ni²⁺ concentration, which meeting the nickel special emission limit of the emission standard of pollutants for electroplating (<0.1mg/L). Furthermore, precipitation dissolution test about Na₂S-DDTC mixed with Ni showed that, the hybrid sediment had a high sability under the state of nature, and did not cause secondary pollution. The particle size distribution was studied and a SEM method was used to observe the precipitation surface, the results indicated Na₂S-DDTC had a certain synergy of flocculation and coprecipitation. Through this study, it could provide theoretical support for process design to deal with wastewater containing high complex Ni concentration using Na₂S-DDTC.