NOVELTY - Synthesis of 2-heptanone comprises taking acetone and butyraldehyde as raw materials and reacting; introducing with solid-based catalyst into fixed bed reactor, reacting, condensing with acetone, condensing with butyraldehyde; dehydrating; distilling, separating unreacted acetone and butyraldehyde, adding to fixed bed reactor, and reacting; adding remaining mixture with hydrogenation catalyst into reactor and reacting; and dehydrating, catalytically hydrogenating, removing water, and rectifying.    USE - Method for synthesis of 2-heptanone (claimed).    ADVANTAGE - The method has shortened process, avoids generating acid-containing waste, and reduces generation of by-product, device investment and production cost.    DETAILED DESCRIPTION - Synthesis of 2-heptanone comprises:    (A) taking acetone and butyraldehyde as raw materials and reacting at 0-60 degrees C and pressure of 0-1 MPa; introducing with solid-based catalyst into fixed bed reactor, reacting to obtain 4-hydroxy-2-heptanone, condensing with acetone to obtain diacetone alcohol, condensing with butyraldehyde to obtain 2-ethyl-3-hydroxy-hexanal; dehydrating to obtain 2-ethyl-2-hexenal;    (B) distilling, separating unreacted acetone and butyraldehyde, adding to fixed bed reactor, and reacting;    (C) adding remaining mixture with hydrogenation catalyst into reactor and reacting at 50-300 degrees C and pressure of 1-10 MPa for 1-30 hours; and    (D) dehydrating, catalytically hydrogenating, removing water, and rectifying.    The mass ratio of reactants acetone and butyraldehyde is 0.85:1-100:1. The water content in the reaction is less than 20%. The solid-based catalyst is alkali or alkaline earth metal hydroxide, alkali or alkaline earth metal oxide, alkali or alkaline earth metal alkoxide, and/or strongly basic ion exchange resin. The catalyst has space velocity of -.1-30 ml/hour/gcat. The hydrogenation catalyst is Raney nickel, carbon, aluminum oxide, or silicon dioxide containing nickel, copper, cobalt, platinum, palladium, ruthenium, rhodium, and/or iridium.