Al2O3/ZrO2 eutectic crystal fibers containing various amounts of Y2O3 were grown by the micro-pulling-down method. The eutectic microstructures and some mechanical properties were investigated as a function of growth rate and doping amount Of Y2O3. Doped with Y2O3, Al2O3/ZrO2 eutectic fibers 0.3-2 min in diameter and 500 min in length have been grown over the range of pulling rate 0.1-15 mm/min. The dominant zirconia phase was changed from monoclinic to cubic as the doping amount of Y2O3 increased. The eutectic microstructures were oriented to a common direction which depended on the growth rate and doping amount Of Y2O3. The uniform lamellar structure obtained at a lower growth rate below 1 mm/min transformed to an ellipsoidal cellular structure at a growth rate above 10 mm/min. and circular or triply facetted cellular patterns were observed at intermediate growth rates. The intercellular spacing increased as the doping amount of Y2O3 increased. The hardness value reached 20 GPa for 9 mol% Y2O3 doped fibers grown at a rate of 15 mm/min. The highest tensile strength reached 2000 MPa at room temperature and 560 MPa at 1500 degreesC for the 3 mol% Y2O3 doped fibers grown at a rate of 15 mm/min.