Due to the extensive applications of SiC fiber-reinforced composite materials in the fields of aviation, aerospace, and nuclear power, there are increasing demands for SiC fibers with both excellent mechanical performance and high-temperature stability. In this work, nearly stoichiometric polycrystalline SiC fibers were fabricated using amorphous Si-C-Al-O fibers with excess carbon and oxygen (C/Si = 1.34, O content: 7.74 wt%). The nearly stoichiometric composition (C/Si = 1.05) of the product fibers was achieved by thermal decomposition of the starting fibers. The fibers were well-crystallized with grain sizes of similar to 200 nm due to sintering at a high temperature of 1900 degrees C. The fibers exhibited a high tensile strength and a high elastic modulus and were composed of SiC grains with twins and stacking-faults, exhibiting intragranular fracture behavior. Furthermore, the fibers maintained their original tensile strength after being maintained at 1800 degrees C for 5 hour or at 1900 degrees C for 1 hour under an inert atmosphere, and they exhibited a high strength retention (97%) after exposure at 1300 degrees C for 1 hour under air. The high-temperature stability and creep resistance of the fibers were comparable to that of commercial Hi-Nicalon S and Tyranno SA fibers.