In order to reduce the impact of heavy metals on the biological treatment system of electroplating wastewater, a lab-scale process combined with hydrolysis reactor and membrane bioreactor (MBR) was used to treat electroplating wastewater. Taking Cu²⁺ and Ni²⁺ as research objects, the effects of different metal concentrations on the electroplating wastewater treatment were studied, and the changes of DOMs and microbial activity in water were analysed simultaneously. The experimental results showed that the removal efficiencies of COD and NH₄⁺-N were above 75% and 45%, respectively, when the concentration of Ni²⁺and Cu²⁺ was 5-20 mg/L. Nitrification bacteria's ability to resist heavy metal impact was weak. The tolerance concentration of Ni²⁺ in hydrolysis reactor combined with MBR was 20 mg/L and only 10 mg/L in MBR. The hydrolysis reactor could convert most of HPI into HPO-A, which could improve the biodegradability of refractory organic compounds, and the content of aromatic compounds was obviously decreased. With the increase of Ni²⁺ and Cu²⁺, the SOUR value of activated sludge in MBR reactor was gradually decreased, but the inhibition rate of SOUR in hydrolysis reactor combined with MBR was 5% lower than that in MBR. Due to the hydrolysis, the toxicity of heavy metals decreased. In hydrolysis reactor combined with MBR, the activity of microorganism was higher, and the content of EPS and the effluent concentration were significantly lower than those in MBR. The formation of colloid, dissolved organic matter and sludge cake layer could be reduced effectively, which retarded the rate of membrane fouling.