Disclosed in the present invention is a method for efficiently preparing succinaldehyde. A microchannel reactor is used, and the method comprises the following steps: step 1, constructing a microchannel
reactor system, the microchannel
reactor system comprising a feeding module, a microchannel reaction module, a
temperature control module, and a product collection module; and step 2, separately pumping an
aqueous solution containing a catalyst and 2,5-dimethoxytetrahydrofuran into the microchannel reaction module by means of the feeding module and mixing for reaction to obtain a succinaldehyde
aqueous solution, wherein the catalyst is
trifluoroacetic acid and 2,2,6,6-tetramethylpiperidine
oxide. In the method for preparing succinaldehyde as provided by the present invention, a microchannel reactor is used, and the present invention has a
fully automated production process, high control accuracy, a safe and stable reaction process, easy operation, low production costs, and a short reaction time, and achieves a high content of succinaldehyde in the resulting succinaldehyde
aqueous solution. The use of a combined catalyst (
trifluoroacetic acid + Tempo) effectively shortens the reaction time, and also inhibits the generation of by-products.