By means of forced non-resonance under 3-point bending method, the internal frictions of 2D-C/SiC composites are carried out from 25°C to 400°C in air. The effects of temperature, amplitude and frequency on internal frictions have been analyzed. Results show that interface layer plays a dominant role to internal friction. When temperature increases from 25°C to 400°C, internal friction of 2D-C/SiC composite increases slightly, and storage modulus decreases monotonically. With frequency increases from 1Hz to 100Hz, internal friction reduces to a minimum around 10Hz, whereas above 50Hz it arises sharply. In amplitude scale from 0.5μm to 10μm, internal friction increases linearly with the increase of amplitude.