As a high-temperature-resistant structural reinforcement material with excellent performance, alumina continuous fiber has been widely used in various fields. However, its large-scale preparation is still a great challenge due to the technical difficulty. Herein, the alumina continuous fibers were prepared using self-made aluminum sol and commercially available silica sol as precursors, in which the microstructure and composition of aluminum sol were studied to reveal their excellent spinnability. Preparation of alumina-based gel continuous fibers with length longer than 1500 m was realized by Sol-Gel combined dry spinning technology. After calcination at 1100 ℃ for 30 min, the continuous ceramic fiber composed of γ-Al₂O₃ and amorphous SiO₂ with the diameter and mean tensile strength of 10 μm and 2.0 GPa was successfully obtained. Microstructure analyses revealed high relative density of the ceramic fibers, in which the γ-Al₂O₃ nanocrystals with size of 10-20 nm uniformly distributed in amorphous SiO₂, resulting in excellent mechanical properties. This preparation process is environment-friendly, simple and controllable, showing great potential in practical application. The test for high temperature resistance revealed that the alumina continuous fiber can work for a long time at 1000 ℃ while it can endure as high as 1300 ℃ for a short-time service.