Abstract: The length of water medium has an important influence on the blasting effect when water infusion blasting is used in the process of tunnel excavation. Therefore，in order to get the distribution law of stress on hole wall of water interval charge，the Starfield superposition method is used to deduce the changing situation of stress on the hole wall，in which the attenuation and superposition of stress wave are considered，and ANSYS/LS-DYNA are used to verify the calculated results.The results show that the stress on the hole wall is the largest at the interface of explosive and water medium.With the increase in the distance from the interface，the explosion stress decreases in the form of exponential function.The equivalent interval initiation method is used to simulate the explosion processes of water interval charges with different charge masses.The attenuation law of simulated explosion stress on the hole wall in the water interval section is consistent with that of the theoretical explosion stress，and the error between simulated and theoretical explosion stresses at the same position is about 10%.The total stress on the hole wall of water interval section increases with the increase in charge mass.In conclusion，it is reasonable to use the Starfield superposition method to obtain the explosion stress formula of hole wall in water interval section.

Key words: waterintervalcharge, explosionstressonholewall, Starfieldsuperpositionmethod, numericalsimulation