Abstract: In order to study the post-explosion damage characteristics of slotted cartridge under different decoupling coefficients, using plexiglass as test material, analysis blasting damage of slotted cartridge with decoupling coefficients 1.33, 1.67, 2.00, 2.33, 2.67.Based on the principle of box counting dimension in fractal theory, compile MATLAB program to calculate the fractal dimensions of the blasting cracks in the cutting slot and the vertical cutting direction under the five kinds of decoupling coefficients.Statistical analysis of crack length and number after explosion, the result shows that within the range of decoupling coefficients selected in the test, the fractal dimension of the crack in the slit direction is significantly larger than the fractal dimension of the vertical slit direction,the slotted cartridge has obvious effect on the control of the crack propagation direction.Among the decoupled coefficients selected in the test, there is an optimal decoupled coefficient of 1.67, under this decoupling factor, the fractal dimension of the crack in the kerf direction reaches the maximum, the crack length is the largest, and the directional control effect of blast damage is the best.After the decoupling coefficient is greater than 1.67, as the decoupling coefficient of the slit-sealing pack gradually increases, the crack propagation length in the slit direction gradually becomes shorter.