Abstract: In order to study the influence of uncoupling charge medium on blasting effect，a new digital laser dynamic caustics test system was used to compare the dynamic crack propagation characteristics of eccentric decoupling charge in water，air and yellow mud. The results show that the explosion shock wave of the eccentric uncoupled charge shows asymmetry，and the shock wave first acts on the eccentric side of the hole and then acts on the non-eccentric side of the hole. When the water is the uncoupled charge medium，the main crack initiation time is the earliest and the peak stress intensity factor at the main crack tip is the largest. In terms of the peak velocity of the main crack propagation，the medium effect is water > air > yellow mud.

Key words: dynamic caustic, eccentric uncoupling, charge medium, stress intensity, crack propagation