Based on the modified Timoshenko beam theory， the transverse vibration governing equation of the modified Timoshen? ko beam on the viscoelastic Pasternak foundation is established. The analytical solutions of the natural frequency and attenuation co? efficient of the modified Timoshenko beam simply supported at both ends in the viscoelastic Pasternak foundation are derived with the reverberation-ray matrix method. The natural vibration characteristics of the modified Timoshenko beam on the viscoelastic Pasternak foundation under classical boundary conditions are calculated by dichotomy and golden section method. The effects of moment of inertia caused by shear deformation， beam length and different boundary conditions on the natural vibration characteris? tics of the structure are compared and analyzed. The results show that the natural frequency and attenuation coefficient of the modi? fied Timoshenko beam on the viscoelastic Pasternak foundation are smaller than those of the classical Timoshenko beam； the short? er the beam， the more significant the influence of the moment of inertia caused by shear deformation on the natural frequency and at? tenuation coefficient of the structure， and the influence on the higher order is obviously greater than that on the low order； the stron? ger the boundary constraint condition， the more obvious the vibration energy attenuation.