Abstract: To study infrared thermographic testing of resin accumulation between panel and honeycomb core, 1D model was investigated and solved by finite element method(FEM) and experiments were made on honeycomb sandwich structure samples which were dissected later in this paper. Results of the model analysis and the experiments showed that areas of resin accumulation were dark in original thermal images and temperatures of these areas were lower than those of normal areas. So areas of resin accumulation could be found out in infrared thermographic testing. Areas of resin accumulation are not defects, but nondestructive testing of resin accumulation is useful for improvement of processing technique of honeycomb sandwich structure components. It would be helpful to find areas where there was water in honeycomb core of components in-service that the position, shape and area of resin accumulation were recorded in advance.