NOVELTY - Preparing (110) silicon monocrystal by floating zone method, comprises (i) installing a furnace, vacuuming, melting material, welding, carrying out seed crystal growth guiding process, setting down-moving speed and rotating speed of lower and upper shafts; (ii) carrying out shouldering process after seed crystal growth guiding process, adjusting down-moving speed of the upper shaft and the power based on diameter of crystal guiding thin neck, adjusting heating power and down-moving speed of upper shaft based on shouldering diameter of crystal; and (iii) carrying out finishing process.    USE - The silicon monocrystal prepared by floating zone method is useful for high-efficient solar cells.    ADVANTAGE - The silicon monocrystal prepared by floating zone method has low impurity and high service life compared to the silicon monocrystal prepared by direct drawing method. The disposition density is not greater than 500/cm2 and the service life is not less than 300 mu s.    DETAILED DESCRIPTION - Preparing (110) silicon monocrystal by floating zone method, comprises installing furnace, vacuumizing, preheating, melting the materials, welding, guiding the seed crystal growth, shouldering and growing with equal diameters and carrying out the finishing process. The method specifically comprises: (i) installing the furnace, vacuuming, preheating, melting the material, welding, carrying out the seed crystal guiding process, setting the down-moving speed and the rotating speed of the lower shaft as 3-5 mm/minute and 10-15 revolutions per minute respectively, setting the down-moving speed and the rotating speed of the upper shaft as 0.5-2 mm/minute and 1-2 revolutions per minute respectively, and carrying out the following operations: (a) gradually increasing the down-moving speed of the lower shaft to 30 mm/minute, continuously adjusting the heating power based on the down-moving speed of the lower shaft and the diameter of the crystal guiding thin neck until the diameter of the crystal guiding thin neck is 6 mm, (b) when the diameter of the crystal guiding thin neck is 6 mm, retaining the fixed power value, setting the down-moving speed of the lower shaft to be 40 mm/minute to reduce the diameter of the crystal guiding thin neck to 2 mm, (c) when the diameter of the crystal guiding thin neck reaches to 2 mm, setting the down-moving speed of the lower shaft as 30 mm/minute to enable the diameter of the crystal guiding thin neck to reach to 6 mm, and (d) repeating the operating processes, changing the diameter of the crystal guiding thin neck in the range from 2-6 mm until the length of the crystal guiding thin neck is not less than the monocrystal by 1.5 times; (ii) carrying out the shouldering process after the seed crystal growth guiding process, gradually increasing the down-moving speed of the upper shaft to 2-4 mm/minutes, gradually increasing the power, when the diameter of the crystal guiding thin neck increases to 8 mm, setting the down-moving speed of the upper shaft as 1.5 plus minus 0.5 mm/minute, gradually reducing the rotating shaft of the lower shaft to 8 plus minus 1 revolutions per minute, when the shouldering diameter reaches to 15 plus minus 2 mm, slowly increasing the heating power and continuously adjusting the down-moving speed of the upper shaft to enable the shouldering angle to be 50 plus minus 5 degrees ; and (iii) carrying out the finishing process after finishing the shouldering and equal-distance growing processes, where the finishing length is 1.2 times greater than the diameter of the monocrystal and the minimum diameter of the finishing part is not greater than 5 mm.