In the past few years, cloud edge system from conception to gradually improve, develop to today has become a mature side of cloud model. Compared with simple cloud computing, cloud edge system has lower network latency and is suitable for application scenarios with higher real-time requirements. Although it can make up for some shortcomings of cloud computing, it also faces many problems in practical application, how to realize the safe transmission of information in the open network environment is one of the difficulties. Since the data transmission process between the edge and the cloud exists in the form of plaintext transmission, this allows attackers to easily disrupt normal data interactions. It is an important research point to ensure the stable operation of the cloud edge system while maximizing the security of communication. To this end, the following work has been done in the direction of secure data transmission in this paper:1. Analyzed the potential risks of the cloud edge system communication network from the per-spective of data source security and data transmission security. 2. Summarizes the requirements and limitations of secure communication, introduces a light-weight SM9 encryption algorithm with low implementation cost and low resource consumption. And compared with other encryption algorithms. 3. Provide algorithmic foundation for establish a framework for secure transmission of light-weight data and achieve data confidentiality protection. Provides a viable reference for secure data transmission in the cloud edge system.