The blasting conditions, topography and geology of rock blasting for expanding cutting at the existing line of electrified railway are more complicated and difficult than that of rock blasting or foundation demolishing blast in cities. The engineering quantity is larger, too. As there has electrify overhead contact line and short space to the existing line, it is much more difficult than blasting for expanding cutting at non-electrified railway. The paper introduces the practicable technology adopted in the light of the features of expanding the cutting for electrified railway existing line in order to attain the purpose of safety and rapid construction.