In this work, the thermoelastic damping of a nano-scale resonator is analyzed by the generalized thermoelasticity theory based on two-temperature model (2TLS). The effect of two-temperature parameter and relaxation time in nano-scale resonator are investigated for beams under clamped conditions. Analytical expressions for deflection, temperature change, frequency shifts, and thermoelastic damping in the beam have been derived. The theories of coupled termoelasticity and generalized thermoelasticity with one relaxation time can extracted as limited and special cases of the present model. The numerical results have been presented graphically in respect of thermoelastic damping and frequency shift.