A novel method for the three-dimensional (3D) printing of continuous carbon fiber-reinforced SiC composites is proposed. A thermally assisted extrusion-based 3D printing system was developed to simultaneously print a thermoplastic SiC ink, which exhibited shear-thinning properties at high temperatures and underwent rapid solidification at room temperature, and continuous carbon fiber bundles. In order to simultaneously improve both the solid loading and rheological behavior of ceramic ink during direct ink writing (DIW) process, the polyelectrolyte complexes have been used as rheological modifiers.  Based on the Funk-Dinger function, the maximum solid loading of multi-sized SiC ink reached 63 vol.%. The viscosity, thixotropy, and printability of the thermoplastic ink were optimized by varying the content of SiC whiskers. Furthermore, the established correlation between the ink composition, nozzle structure, and printability demonstrated that fiber deviations in filaments could be minimized by selecting an appropriate whisker content and flat coaxial nozzle. A trade-off between the dimensional accuracy and mechanical properties of the printed materials was achieved by optimizing the ink composition and nozzle structure.