Abstract: The coupled torsional and flexural vibration of a continuous shaft is studied, considering the misalignment of locus of the mass centers and that of the shear centers. The equations of coupled torsional-flexural vibration are established. The exciting torque, the damping properties and the eccentricity are taken into consideration in the equations. The coupled torsional-flexural vibration of a continuous simply supported shaft model with damping is studied, in which only the weight of the shaft itself is considered. The measurement in a practical simply supported copper shaft with constant section is made. The calculation results are compared with those of the measurement. It is found that the 1st, 3rd, 5th, … modes of the flexural vibration are coupled with the 2nd, 4th, 6th, … modes of the torsional vibration; the 2nd, 4th, 6th, …modes of the flexural vibration are coupled with the1st, 3rd, 5th, …modes of the torsional vibration.