In the satellite Internet of Things(IoT) scenario, as the number of terminals continues to increase, the spectrum resources are of shortage increasingly, and the traditional random access technology has low spectrum utilization, making the traditional random access protocol unsuitable for the high concurrent service requirements of the future satellite IoT. At the same time, satellite communication links are long and open, making it difficult to guarantee the security of special terminal signals. This paper proposes a hybrid random access scheme suitable for satellite Internet of Things. This scheme introduces the capacity improvement and security advantages of overlapping transmission, utilizes the ability of spreading code to control the instantaneous power spectral density, constructs non-orthogonal access conditions in the power domain, and achieves robust reception through iterative separation at the receiving end. The derivation analysis and computer simulation of the throughput performance of the proposed scheme are carried out. The simulation results show that the proposed scheme can improve the system throughput compared with the traditional random access protocol. At the same time, compared with common signal concealment methods, the proposed method utilizes the power advantage of conventional access data packets to strengthen the waveform concealment effect and improve the security of special information access.