A method for continuous synthesis of acylnaphthalene includes: mixing a raw solution containing 2-methylnaphthalene with an acylation liquid to obtain an acylation reaction liquid with a molar ratio of the 2-methylnaphthalene: the acylation agent: the Lewis catalyst of 1:1.3:1.5; adding the acylation reaction liquid into a microchannel reactor and a plurality of kettle reactors connected in series to perform acylation reaction, performing hydrolysis reaction on the acylation reaction liquid immediately after the acylation reaction liquid flows out of the plurality of kettle reactors to obtain a mixed solution, and subjecting the mixed solution to separation, rectification and crystallization, to obtain 2-methyl-6-propionylnaphthalene.