Abstract: Since impoundment in 1998, after 8- year operation without Ohmic heating, asphalt leakage at the dam transverse crack asphalt wells of different degree happened. To ensure the expansion joint sealing system work in order, in November 2006, melting by Ohmic heating was carried out to all asphalt wells, then bituminous cement grouting followed. After treatment, no leakage was found at damexpansion joints, good effect was achieved. This paper analysed and summarized the treatment technology and method ofmelting by Ohmic heating combined with grouting to damexpansion joints at Wanjiazhai hydropower station.