Based on the principle of cumulative charge explosion,a new kind of rock cutting blasting technique,the jet perforator charge blasting in small diameter boreholes,is developed in this paper. One jet perforator charge can creat two stream of jets in the opposite directions which can drill a pair of perforations face to face in the radial of the borehole. Several charges are loaded in one borehole in all. After the charges initiated at the same time,a line of jet perforations occurs on the wall of the borehole,so that the rock cracks and fractures in the jet perforating direction. According to the theory of fracture mechnics,the formula of the blasting parameters are derived. The results of the typical experiments on site show that the jet perforation blasting method is a practical technique for prestlit blasting,smooth blasting or rock material mining etc.