In order to improve the coupling efficiency between the single-mode fiber and the nano-silicon-wire waveguide in silicon-on-insulator (SOI),a novel tapered spot-size converter (SSC) is designed,which is constructed with a tapered silicon waveguide and an overlaid rectangular hybrid sol-gel SiO₂ waveguide. Simulation analysis,which is performed with the three-dimensional beam propagation method (3D-BPM) at λ=1550 nm with semi-TE polarization,shows that the coupling efficiency can be up to 95% (loss of 0.22 dB),which is very promising for high coupling efficiency between the single-mode fiber and the nano-silicon-wire waveguide.