Abstract: In order to increase numerical calculation accuracy of hexagonal aluminum honeycomb sandwich plate, influences of length-thickness ratio on dynamic calculation accuracy of equivalent plate models were discussed. For the hexagonal aluminum honeycomb sandwich plate with cores which has uniform thickness of walls, equivalent plate models, including Reissner theory model, honeycomb plate theory model and the low-order shear laminated plate theory model were analyzed firstly. Then, natural frequencies of equivalent plate models were compared with those of the detailed model when their modal shapes were same. And influences of length-thickness ratio on the dynamics calculation accuracy of the equivalent plate models were analyzed. The results show that the calculation error on the natural frequencies of the homogenized core model is small; the low-order shear laminated plate theory model is a equivalent plate model with higher calculation accuracy; calculation accuracy of Reissner theory model is the lowest when length-thickness ratio is 7.37; the calculation accuracy of honeycomb plate theory model is lower on slab than on sheet; and the calculation accuracy of low-order shear laminated plate theory model is higher on slab than on sheet.