Abstract: Based on the experimental study of compressive failure mechanisms on composite honeycomb core sandwich panels after low speed impact before, a equivalent delamination was used to replace the low speed impact damage of Nomex honeycomb core sandwich panels in this paper. It was postulated that the edge of sublaminate formed by the equivalent delamination is clamped. The load on which the sublaminate buckled was considered to be compressive failure load. Comparing the results of theory with experiment, it showed that the method of equivalent damage could be used to predict the residual compressive strength of honeycomb core sandwich panels, in the case that the facesheet of sandwich panels had no obvious cracks after low speed impact.