A collaborative team from Shanghai Jiao Tong University and Shanghai University of Electric Power has attained a significant breakthrough in quantum direct communication technology. They have successfully established a fully-connected quantum direct communication network spanning 300 kilometers and featuring four nodes. This innovation transcends the constraints of conventional architectures by optimizing light source preparation technology, thereby enhancing transmission distance. Additionally, the team has implemented an error correction mechanism to guarantee reliable multi-node communication. This achievement paves the way for the practical deployment and widespread application of quantum communication networks.