Abstract: In order to study the mechanical behavior characteristics of dynamic crack initiation and propagation of surrounding rock of adjacent roadway under impact load, with the help of a new digital laser dynamic caustics experimental system, a rock-like medium material PMMA was used to make a double-section roadway model for impact tests, and the crack propagation simulation was carried out based on the ABAQUS numerical simulation platform. The results show that when the pre-crack deflection angle α of adjacent sections is 45°, 22. 5°, 0°, -22. 5°, -45°, the dynamic stress intensity factor are different when the cracks were initiated. The dynamic stress intensity factor change after crack initiation has a "platform section" with a duration of about 160 μs. When the right crack gradually moves away from the left cross-section, the crack propagation speed of left crack after initiation will increase. When the dynamic crack initiation and propagation of the double-section roadway, the adjacent sections will affect the dynamic stress intensity factor and propagation speed to a certain extent. When the tip of the right crack is close to the left crack, the latter's crack initiation toughness is reduced, that is, it is easier to crack.