In order to establish a reliable data transmission system of mobile station, a reliable communication link based on BDS short message protocol is designed. Aiming at the shortcomings of BDS short message communication and the limited communication capacity, through the self defined communication protocol, enhanced data mobile phone system is adopted to enhance the reliability of data transmission and simultaneous interpreting data transmission mechanism of multi card, which improves the efficiency of data transmission. The experimental results show that the reliability of the data transmission in Beidou satellite mobile station can be guaranteed by using the reliable communication link design proposed in this paper, which is 35% higher than that of the traditional method.