The influence factors on the penetration depth of shaped charge jet were summed up by analyzing the formation of shaped charge jet and penetration. According to the factors and the condition of engineering practice,a sort of the flexible and linear shaped charge cutter was designed. The target steel plate with the thickness of 10 mm was penetrated through by the linear density 158 g·m^-1 and blasting height 2.4 mm of the flexible and linear shaped charge cutter with lead shell from experiments. This type of cutter was used for cutting inclined brace steel tube in the steel tower blasting demolition that made an accurate collapse. Finally, the inclined brace steel tube with thick wall was penetrated through by the cutter, the direction of collapse was inerrability and the steel tower blasting demolition was very success.