Abstract: Impact rock breaking technology is widely used in hard rock drilling due to its high drilling efficiency, but the intrusion and crushing characteristics of soft rock under impact load are not clear. Based on the orthogonal design test theory, a similar material selection and proportioning scheme was designed, and similar soft rock materials were prepared by pouring in accordance with the geo-mechanical characteristics of soft rock. The indoor impact rock-breaking test device with equal structure including impact drop hammer, spherical toothed anvil body and sample fixture has completed the dynamic simulation and obtained the load curve diagram. On these basis, the finite element joint simulation of multi-body dynamics and transient dynamics and the indoor simulation experiment of impact rock breaking are carried out. The results show that the soft rock presents typical plastic crushing characteristics under impact load, the crushing characteristics are not obvious, the shape of impact pit is regular and the volume of rock debris is small. The intrusion depth of impact ball tooth in soft rock is closely related to impact energy, impact times and ball tooth specification. There is a limit intrusion value in the process of soft rock intrusion.