To explore the influence of different initiation methods on the damage distribution on both sides of the air-spaced charge blasthole, polymethylmethacrylate (PMMA) was chosen as the experiment material. With the help of digital image correlation (DIC) experimental system, the evolution process of the whole field strain field and the strain attenuation law of the air section are obtained. At the same time, by means of the dynamic caustics experimental system, the influence of the detonation method on the dynamic fracture behavior of the prefabricated crack was explored. The experimental results show that the damage range generated on both sides of the blasthole of the cylindrical charge has significant fractal characteristics. When the outer-detonation is used, both sides of the center of the air section are damaged, but when other detonation methods are used, the air section is not damaged. The influence of different initiation methods on the radial compressive strain of the air segment strain field is mainly reflected in the two aspects of strain size and decay rate, and the influence on the axial tensile strain is mainly reflected in the two aspects of timeliness and decay rate. The fracture behavior of pre-crack ends varies greatly under different detonation methods. When the inner-detonation and outer-detonation are used, the cracks expand horizontally, showing typical type I and the crack initiation is mainly caused by tensile failure. When the antarafacial-detonation is used, the crack initiation is of the type I-II mixed, and the specific performance is tensile-shear destroy. Based on the numerical simulation software LS-DYNA, the origin of the crack initiation at the end of the pre-crack was explained, and the distribution law of the stress field at the blasthole wall was obtained. Different detonation methods have significant effects on the pressure distribution along the axial hole wall of the blasthole. The charge section is mainly reflected in the position of the pressure peak and the pressure distribution shape, and the air section is mainly reflected in the pressure peak size and the pressure distribution shape.