Abstract: In the modern communication network design, the user wants high communication reliability with the least possible cost of the communication system. The cost of communication links includes both direct costs and indirect costs arising from the interaction of different communication links. A minimum spanning tree model with double constraints is established
so as to provide the scientific research, teaching and management with a better network service at a reduced cost for the school. Since currently no effective algorithm is found to solve the new model, efforts has to be made to solve the fiber optic cabling optimization on campus through quadratic minimum spanning tree to ensure the reliability and economy of communication.