The pull out conditions of M5 inserts in honeycomb sandwich structures were tested. Results were
discussed and the effects of sample dimension, vacuum pressure, amount of foaming resin and honeycomb insert height differences on the pull out strength were analyzed. It was found that the pull out strength were not affected when the honeycomb insert height step was between 0. 15 and 0. 40 mm. In order to avoid the boundary effect, the sample dimension should be at least twice of the aperture of the testing clamp. For J 47D foaming resin, it is helpful to the pull out strength during the pressure loading or the vacuum unloading when the temperature has reached T1.Moreover, optimization of the foaming resin around the inerts can improve the pull out strength. The conclusions canbe used in product design experiments and processing parametric initiation.