Abstract: In 5G communication network with limited terminal resources, in order to solve the problems of access authentication security, such as the complexity of certificate management in traditional public key cryptography, key escrow in identity-based cryptography, and the vulnerability to quantum computing attacks, combining 5G with post-quantum cryptography, based on the previously improved PolarRLCE public key encryption scheme and combined with the improved Xinmei signature scheme and certificateless aggregate signcryption model, a certificateless aggregate signcryption scheme based on polar code in 5G network is constructed. The new scheme to the military vehicle network in 5G combat scenarios.