Molecular dynamics simulations were performed to investigate CF3 continuously bombarding SiC surfaces with energies of 10, 50 and 100 eV at normal incidence and room temperature. In the simulation, the deposition yield of C and F atoms from CF3, the etching yield and rate of C and Si from the initial substrate, and the surface structure profile are discussed. Accompanying the saturation of F atoms from the incident CF3 molecules deposited on the surface, a balance between C removal from the substrate and C deposition from CF3 is established, while Si and C etching from the initial substrate reaches a steady state. The simulated results show that the etch rate of Si is more than that of C. A carbon-rich surface layer is observed which is in good agreement with experiments. In the F-containing reaction layer, SiF in SiFx species is dominant.