For the A, B, C, D four kinds of modified middle-deep hole blasting, detailed calculating the blasting load length of the four styles and comparing with normal middle-deep hole blasting. By spectrum analysis of asymmetric triangular load, drawing the conclusion of inverse proportional relationship between load duration and frequency. On the base of it, the study shows modified styles improve blasting vibration frequency to some extent, reduce the chance of building resonance, and achieve the goal of increasing frequency and decreasing amplitude. Take the engineering program of open-cut subway station at Xinzhaizi of Dalian city which uses joint blasting technology of combining the shallow hole with modified middle-deep hole of A and C styles for example. The program achieves the aim of reducing cost and shorting the time limit.