Abstract: Low temperature electrostatic precipitator is a technology to simultaneous control of fine particle and SO₃ for coal-fired power plants. The removal of fine particle and SO₃ from coal combustion by low-low temperature electrostatic precipitator was investigated experimentally based on the coal-fired thermal system. The influence factors, including inlet temperature and SO₃ concentration were analyzed. The mechanism of fly ash adsorption SO₃ was discussed. The results show that fine particle size increases apparently contrast with the traditional ESP at the outlet. Decreasing the temperature and raising the SO₃ concentration have a positive effect on improving the removal of fine particle and SO₃. the removal efficiency of SO₃ is higher than 80% by Low Temperature Electrostatic Precipitator. Condensation of SO₃ on fly ash is mainly controlled by internal diffusion.