The composite aerogel fibers were prepared with green organic material bacterial cellulose and doped with reinforcing material thermoplastic polyurethane elastomer using wet spinning. The prepared aerogel fibers were structurally analyzed and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), thermogravimetric analysis (TG), scanning electron microscopy (SEM), automatic specific surface porosity analyzer and monofilament strength meter, and the results showed that the composite aerogel fibers have porous structure, good mechanical properties and thermal insulation, with a breaking strength of 24.69 Mpa and an elongation at break of 38.54%.