Microstructure and static mechanical properties of 3D-SiC/SiC composites with different interfaces, such as PyC, SiC and PyC/SiC and without an interface were prepared via polymer infiltration and pyrolysis, and effect of interface type on the internal friction was investigted by means of forced vibration. The results showed that the microstructure and static mechanical properties of SiC/SiC composites with an interphase layer were superior to the composites without an interlayer, and the former also showed a lower internal friction than the later. The sub-layer SiC of the PyC/SiC interface limits the binding state and the plastic deformation of PyC interphase, beneficial to improving the mechanical properties of SiC/SiC composite. Meanwhile, The interface layer of SiC/SiC composites has a significant effect on the internal friction behavior, with interfacial shear strength inversely proportional to the internal friction. By comparing the change rate of internal friction of composites at 50 and 350 ℃, the overall trend of internal friction decreases with the increase of interfacial shear strength. In addition, as compared with the composite with PyC interface, the composite with PyC/SiC interface has a lower change rate of the internal fiction, indicating that PyC/SiC interface of SiC/SiC composites is more helpful for high temperature vibration environment.