Based on Levinson beam theory and unidirectional coupled non-Fourier heat conduction theory, the thermoelastic damping (TED) of uniform micro beams with different boundary conditions was studied. Neglecting the heat flow caused by the axial gradient of temperature, the differential equation of free vibration of Levinson micro-beam was given. According to the similarity of equation forms, the analytical solution of characteristic frequency is obtained, and then the inverse quality factor representing the TED of micro-beam structure was obtained. Then, the inverse quality factor of the micro beam structure considering the non-Fourier heat conduction was calculated by the finite element method, and the finite element results are compared with the theoretical analysis results. Based on the numerical results, the influence of the geometric size, boundary conditions and vibration mode of the micro-beam on the TED were analyzed quantitatively. The results show that: (1) when the micro-beam vibrates at different frequency orders, the maximum value of TED remains unchanged and the critical thickness decrease with the increase of the order of vibration mode; (2) Under different boundary conditions, the critical thickness corresponding to the maximum TED of the micro-beam decreases with the increase of the constraint stiffness of the support; (3) Ignoring the heat flux caused by the axial temperature gradient will bring some errors when the beam size is small.