Limited by the size of model test chamber， the reflection wave generated by explosion load on the boundary of test chamber would inevitably affect the expected results in the centrifugal tests of underwater explosion. Therefore，reducing the boundary effect will substantially restore the actual test situation and improve the test accuracy. Numerical simulation on centrifuge model test of underwater explosion was conducted based on the Coupled-Eulerian-Lagrangian（CEL） method，. Through comparing experimental results with theoretical results and analyzing mesh sizes of 1， 2， 4， 6， 8 and 10 mm， the reliability of the numerical model was verified. Based on that， the shock wave propagation characteristics in centrifuge tests of underwater explosion with boundary energy absorbing materials of rubber and foam （thicknesses of 5， 10， 15 and 20 mm） were compared， and the mechanism of wave absorption and energy dissipation was analyzed. The results show that the Euler mesh size of 2 mm could balance the calculation efficiency and accuracy of calculation results. Laying rubber or foam materials on the inner wall of the model chamber could effectively reduce the reflection effect of underwater explosion shock waves. The rubber material is more effective in shock wave absorption than the foam material for the condition of 5 mm thickness. However， with the increase of material thickness， the foam material has a better absorption effect than rubber. Both rubber and foam materials have a certain inhibitory effect on low-frequency signals of shock waves， but the inhibitory effect on high-frequency signals is weak.