With the opportunity of the digital transformation of the vertical industry represented by the power grid in the 5G era, in order to meet the communication needs of all kinds of new services in the power grid application scene, in order to adapt to the comprehensive perception and intelligent interconnection development of the future power grid under the new situation, the intelligence of the power Internet of things supporting Yunbian collaboration needs to be improved urgently. Under the 5G architecture, how to effectively protect the business data of communication terminals has become the focus of relevant developers in the security industry. In order to solve the problem of illegal intrusion of equipment and secure data transmission, a big data security access processing device based on 5G is designed in this paper. In this device, the access terminal authentication module authenticates the user identity information through audio and video, two-dimensional code and other technologies; the data trust verification module confirms the data security through whitelist, data scanning and other methods; the data software and hardware encryption module encrypts the data through encryption chip and IPSEC protocol and other technologies. Combining these technologies, the secure transmission of network data is realized. In addition, by testing the throughput of the encryption algorithm, it is found that the smaller the key value of the encryption algorithm, the greater the throughput.