This study conducts a laboratory measurement on a cylindrical electrostatic precipitator(ESP) with a 30mm-diameter cylinder. Several kinds of test aerosols are generated with an atomizer and a diffusion dryer. The effects of applied voltage, flow state, gas velocity, and gas temperature on the electrical characteristics of the precipitator and onset of corona are experimentally investigated. The corona onset voltage is decreased, as diameter of discharge electrode wire becomes small or temperature of the precipitator increases. As the fluid velocity or particle load in the precipitator increases, the corona current is decreased.