Natural disasters are the main factors of the transmission line fault. Based on the statistical analysis of main natural disasters of 500 kV transmission lines in the central China power grid, this paper investigated the accident cases according to the disaster type, time, areas, season and other factors. Several main disaster mechanisms and prevention strategies for the 500 kV transmission lines were studied. At last, this paper presented some suggestions for the disaster resistance and reduction, which could provide references for the safe and stable operation of the transmission lines.