Abstract: When forming curved honeycomb sandwich structures, it needs to mill the honeycomb core into a curved shape, resulting in inclined cell walls of honeycombs and reducing its mechanical properties. A detailed finite element model was introduced to analyze the mechanical response and deformation mechanism of inclined honeycombs, and then verified by means of experiments using a specially designed set-up. The simulated results agree well with the experimental ones in terms of the crushing behavior and collapse mechanism. After that, the validated model was used to evaluate the effect of the inclined cell wall angle range from 0° to 40° on the crushing behavior of honeycombs. It is found that the inclined cell wall angle has a significant effect on the crushing response, and the mechanical properties of honeycomb decrease as the inclined cell wall angle increases. When the inclined cell wall angle varies from 0º to 40º, the maximum reduction of initial peak stress and the plateau strength is 47.7% and 29%, respectively. Moreover, the relationship between the dimension of cross-section about inclined cell wall honeycomb cores and the inclined angle was analyzed. The collapse stress of honeycomb under out-of-plane compression and shear loading is deduced by equivalent the inclined cell wall honeycomb as a vertical cell wall honeycomb with the same cross-section dimension, which reveals the influence mechanism of inclined cell wall angle on the properties of honeycombs.