Decoupled charge can change the action mode of explosive products on rock,so as to obtain different effects of rock fragmentation.In order to study the influence of charge decoupling coefficient on rock crack propagation by blasting under initial stress,a kind of transparent material conforming to the mechanical properties of hard rock was used to carry out similar model tests of blasting under bidirectional equal load.The test results show that:The propagation of the longest radial crack is along the direction of maximum principal stress in the model specimen with equal confining pressure; nder the initial stress state,the decoupling coefficient has an obvious effect on the crack propagation.Both the length of the longest radial crack and the average length of radial main cracks on the model specimens decrease with the increase of decoupling coefficient.And the maximum and average diameters of circumferential fractured zone decrease with the increase of decoupling coefficient; Under the initial stress state,the diameter of the crushed zone increases first and then decreases with the increase of decoupling coefficient.During blasting excavation of deep rock mass,the relationship between the propagation length of the radial main crack and decoupling coefficient can be used to design parameters of controlled blasting,so as to reduce the overcutting and undercutting on surrounding rock and enhance the efficiency of tunneling blasting.The research results are of great significance to enrich the theory of deep rock blasting and engineering practice.