Abstract: Position indicating radio beacon gets great impact load when being put into water，maybe damaging the device structure and inner components．Because of the lack of impact load parameters when being designed，the beacon must have extra volume and weight in order to satisfy the impact requirements．However，water-entry impact load parameters can be got easily and conveniently through finite element analysis．In this paper，based on ANSYS/LS-DYNA，the finite element analysis model of the water-entry course of position indicating beacon is established on the assumption that the beacon is rigid body．Some parameters such as maximum impact acceleration and impact time were got after water-entry simulations with different speeds and gestures，which could become mechanical input parameters of structure design．