Abstract: Carrying out the risk assessment of lightning disaster and choosing the most suitable prevention program is an important means to prevent and reduce the casualty loss caused by lightning disaster, which is also a significant prerequisite for the scientific lightning protection. The author studied the lightning disaster risk of Yangtze River Bridge in Maanshan City Anhui Province, with the help of daily lightning data from 2006 to 2013 monitored by the ADTD type lightning location system of the weather bureau in Anhui Province, applying IEC 62305 specifications and GB/T 21714 national standards. The result showed that the risk of casualty loss mainly came from the contact caused by direct lightning stroke of the bridge, step voltage and physical hazard; the risk of financial loss mainly came from physical hazard and the equipment loss caused by built-in system malfunction of the bridge led by the direct lightning stroke and nearby lightning stroke. The author compared the bridge’s value-at-risk of lightning disaster at the three setting programs in the absence of LPS, LPSⅢand LPSⅡ, and made sure the most optimal program of lightning protection for Yangtze River Bridge in Maanshan so as to reduce casualty loss risk and financial risk value. Part result of the risk assessment had got practical application in the construction of Yangtze River Bridge in Maanshan, meanwhile, the project had achieved the requirement of lightning protection and no lightning disaster has happened till now.