Abstract: By assuming the structure to be continuous, the Hamiltonian dual system of coordination analysis is established for tube-in-tube structures, in which the shears and flexures of the inter and the outer tubes are considered as Timoshenko beams. The state space equations are deduced, in which the system matrix has the symplectic characters. The high accuracy numerical solutions of the system are obtained using precise integration method. Thus a new method for coordination analysis of the tube-in-tube structures is proposed. Using the method in coordination analysis of the tube-in-tube structures is simple and clear. A computer program was also coded and it can be applied to the preliminary analysis of such structures, which provides a more accurate basis for structure plan determinations and structure designs.