Composite material has so much superiority in the field of design, technology and loss of structure weight that its rate of application in the aircraft manufacturing is higher and higher. The composite material based design procedure of the root fairing of vertical tail has been analyzed and discussed detailedly in this article, and it concretely contains the general arrangement of fairing, the spread design of composite material based panel, the design of aerodynamic seals, the design of surface protection, the design of assembly, etc.