The influence of fog water conductivity on conductor corona discharge quantity is seldomly studied. In order to understand the conductor corona characteristics, we adopted the ultraviolet imager, partial discharge detector, ultrasonic atomizer, and oscilloscope to conduct experiments in a corona cage. By applying pulse current method, we studied the influence of electric field intensity, fog water conductivity, and conductor roughness on conductor corona discharge quantity and corona discharge characteristics. Study results show that when water droplet emerges on the conductor surface, the fog water conductivity will have a significant influence on corona discharge quantity, the corona discharge quantity will increase with the growth of fog water conductivity when subjected to the same electric field intensity; and the corona discharge quantity will grow with the electric field intensity, but the discharge quantity tends to be saturated when the electric field intensity reaches a certain threshold value; in addition, the discharge quantity is related to the conductor roughness closely, the harsher of the conductor surface, the bigger of the conductor corona discharge quantity is. It is recommended that the effect of fog conductivity should be taken into consideration when studying the wire corona discharge quantity in fog. © 2018, High Voltage Engineering Editorial Department of CEPRI. All right reserved.