The invention discloses a preparation method for roflumilast intermediates. The preparation method includes: 1), adding 3, 4-dihydroxybenzaldehyde and methyl bromodifluoroacetate into acetonitrile for contact reaction at the temperature of 30-45 DEG C in the presence of hydroxylamine, adding water after reaction completion, extracting and concentrating dichloromethane, and performing petroleum ether recrystallization to obtain 3-hydroxy-4-diflouromethylbenzaldehyde; 2), adding the 3-hydroxy-4-diflouromethylbenzaldehyde and bromomethyl cyclopropane into the acetonitrile for hybrid reaction in the presence of N-methylmorpholine and zinc salt at the temperature of 55-60 DEG C to obtain 3-cyclopropylmethoxy-4-(difluoromethoxy) benzaldehyde; 3), subjecting the 3-cyclopropylmethoxy-4-(difluoromethoxy) benzaldehyde and oxidizing agent comprising MnO2 and HClO to oxidation reaction at the temperature of 45-50 DEG C to obtain 3-cyclopropylmethoxy-4-(difluoromethoxy) benzoic acid. The preparation method has the advantages that selectivity is high and yield is increased; conditions are milder, influences on other groups are avoided and by-products are fewer.