AbstractAlumina fibers were obtained from the poly[((3‐ethoxypropanoyl)oxy)aloxane] (P‐3EPA) by using a polymeric precursor technology. The rheological properties of the concentrated solution of P‐3EPA related to the extrusion and spinning processes have been investigated to determine the processability into fine filaments. Thirty weight percent P‐3EPA dissolved into toluene showed an excellent spinnability and fine filaments of 20–30 μm in diameter were easily obtained. The phase changes during the sintering of the fiber were studied with wide‐angle X‐ray diffraction and were shown to be strongly related to the mechanical properties of the fiber. Further the addition of the ethyl silicate (ES) as a sintering agent which prevent the crystal growth of Al2O3was found to be effective to improve the mechanical properties of the