NOVELTY - Blonanserin is prepared by adding sodium ethoxide to anhydrous ethanol, stirring and dissolving, cooling to 20-30 degrees C, adding ethyl acetoacetate, stirring for 30 minutes, concentrating solvent under reduced pressure until dry, adding residue to ethyl fluorobenzoate, heating and reacting at 150 degrees C for 6 hours, cooling to 20-30 degrees C, adding water to adjust pH to 1-2, standing and stratifying, washing organic layer until neutral, drying to obtain ethyl fluorobenzoyl acetate yellow oil, adding aqueous ammonia and ethanol, stirring and reacting at 20-30 degrees C for 48 hours, filtering, and washing.    USE - Preparation of blonanserin.    ADVANTAGE - Preparation of blonanserin has good product quality and high yield, and preparation is simple and has low energy consumption and cost.    DETAILED DESCRIPTION - Blonanserin is prepared by adding sodium ethoxide to anhydrous ethanol, stirring and dissolving, cooling to 20-30 degrees C, adding ethyl acetoacetate, stirring for 30 minutes, concentrating solvent under reduced pressure until dry, adding residue to ethyl fluorobenzoate, heating and reacting at 150 degrees C for 6 hours, cooling to 20-30 degrees C, adding water to adjust pH to 1-2, standing and stratifying, washing organic layer until neutral, drying to obtain ethyl fluorobenzoyl acetate yellow oil, adding aqueous ammonia and ethanol, stirring and reacting at 20-30 degrees C for 48 hours, filtering, washing filter cake with water, draining to obtain crude product, recrystallizing with ethanol to obtain 3-(4-fluorophenyl)-3-oxopropanamide white solid, adding cyclooctanone, p-toluenesulfonic acid, and toluene, stirring, heating and refluxing for 8 hours, cooling to less than or equal to 50 degrees C, concentrating under reduced pressure until dry, cooling to 20-30 degrees C, adding residue to dichloromethane and water, stirring, standing and separating, washing organic layer until neutral, drying, recrystallizing with isopropanol to obtain 4-(4-fluorophenyl)-5,6,7,8,9,10-hexahydrocyclooctane(b)pyridin-2(1H)-one, adding benzene phosphonoacetyl dichloride, stirring, heating and reacting at 170 degrees C for 1.5 hours, cooling to 20-30 degrees C adding dichloromethane, adding dropwise to ice water, maintaining temperature at 0-10 degrees C, adjusting pH to 8-9, extracting with dichloromethane, combining organic layer, drying, recrystallizing with anhydrous ethanol to obtain 2-chloro-4-(4-fluorophenyl)-5,6,7,8,9,10-hexahydrocyclooctane(b)pyridine, adding potassium iodide (KI) and N-ethylpiperazine, stirring, heating and reacting at 170 degrees C for 14 hours, cooling to 20-30 degrees C, pouring 1st ethyl acetate:water with ratio of 5:1, separating aqueous layer, washing organic layer until neutral, extracting with hydrochloric acid, adjusting hydrochloric acid layer pH to 8.8-9, extracting with 2nd ethyl acetate, combining ethyl acetate layers, washing until neutral, drying, and recrystallizing with anhydrous ethanol.