TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (claimed): Compound (I) is prepared by taking compound (II), dibromo-fluorene derivative of formula (V) and catalyst at mol ratio of 1:1:0.005-0.05, dissolving in aqueous sodium carbonate solution based on 5-10 times by mol compound (II), adding toluene solvent, reacting under reflux at 60-100 degrees C for 24-72 hours, and separating and purifying. Compound (II) is prepared by taking compound (III), injecting into tetrahydrofuran solvent, slowly adding n-butyllithium at compound (II) to n-butyllithium mol ratio of 1:2-4 at - 70 to - 85 degrees C, reacting while stirring for 0.5-4 hours, slowly adding 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane at n-butyllithium to 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane mol ratio of 1:2, heating to room temperature, reacting for 10-48 hours, and separating and purifying. Compound (III) is prepared by dissolving compound (IV) in tetrahydrofuran solvent, stirring, adding 1 mol/L diethyl ether in alkyl magnesium bromide at - 5 degrees C under protection of nitrogen at compound (IV) to alkyl magnesium bromide mol ratio of 1:2.0-2.4, reacting at 0 degrees C for 35-40 minutes, adding 0.1 mol/L copper tetrachloride in lithium-tetrahydrofuran solution at compound (IV) to copper tetrachloride in lithium-tetrahydrofuran solution mol ratio of 25-50:1, reacting while stirring for 4-8 hours, reacting with 10% sodium hydroxide solution for 10-20 minutes, and separating and purifying. Compound (IV) is prepared by dissolving 2,7-dibromo-fluorene in anhydrous dimethyl sulfoxide at room temperature under nitrogen protection, uniformly stirring, adding potassium tert-butoxide at 2,7-dibromo-fluorene and potassium tert-butoxide mol ratio of 1:2.0-2.4, injecting carbon disulfide at 2,7-dibromofluorine to carbon disulfide mol ratio of 1:1.0-1.2, reacting while stirring for 10-20 minutes, adding methyl iodide, continuously stirring for 4-6 hours, and separating and purifying. Preferred Method: Separating and purifying of compound (I) comprises adding toluene and deionized water, extracting, taking organic phase by vacuum-distilling, evaporating to 5-15 mL, dropping into anhydrous methanol, continuously stirring, precipitating, filtering, drying to obtain solid powder, dissolving in chloroform, removing catalyst by neutral aluminum oxide chromatographic column and spin-drying. Separating and purifying of compound (II) comprises washing with saturated sodium chloride solution, extracting with chloroform, drying with anhydrous sodium sulfate or magnesium sulfate, collecting, rotationally evaporating solvent to obtain crude product and separating in silica gel chromatographic column using leaching liquid. Separating and purifying of compound (III) comprises filtering with diatomite filter, collecting, extracting with ethyl acetate, washing extract with 10% sodium hydroxide solution, sodium pyrosulfite solution and saturated brine solution, drying by sodium sulfate, vacuum-distilling, separating with petroleum ether in silica gel chromatographic column, vacuum-distilling at - 35 to - 40 degrees C and recrystallizing with 2-methylpentane as solvent. Separating and purifying of compound (IV) comprises pouring into ice-water mixture, adding concentrated ammonia water to remove unreacted methyl iodide, filtering, washing with water, drying and extracting with ethyl acetate and tetrahydrofuran mixed solvent.