the short message communication function of the Beidou Satellite Navigation System(BDS) has a certain limit on the transmission capacity and transmission frequency. In emergency situations, in order to carry out information interaction accurately and efficiently, a set of emergency transmission mechanism is proposed by improving the short message transmission protocol. The information is divided according to the emergency degree, and the corresponding processing method is adopted. It can send priority information in the limited transmission space, increase transmission efficiency, and provide information interaction guarantee for emergency handling.