Coal-burning pollution caused harmfully to human and environment. However, the efficiency of electrostatic precipitator (ESP) for PM2.5 is low. Reducing the ESP inlet temperature is widely concerned. This technology could simultaneously control of PM2.5 and SO3. In this study, a lab-scale low temperature ESP performance was designed under controlled conditions, the operating effects were evaluated under different temperature and SO3 concentration, SO3 and particles coagulation mechanism was discussed. Experimental results show that the operating temperature was important for ESP, The ESP outlet particle size showed a increasing trend that the median diameter d(50) increased to 0.08 mu m from 0.05 mu m, and the d(90) increased to 0.23 mu m from 0.09 mu m with the inlet temperature reduced from 150 degrees C to 90 degrees C. Particle removal efficiency increased when ESP inlet temperature reduced, especially particles with diameters of around 0.1-1 mu m increased obviously. SO3 removal efficiency improved from about 20% to above 80%, when the ESP inlet temperature drops below the acid dew point. Furthermore, SO3 binary nucleation mechanism was discussed, the analysis results of the adsorption mechanism indicated that SO3 condensation on the fly ash was mainly controlled by internal diffusion. (C) 2017 Published by Elsevier B.V.