The invention relates to a preparation method of a Balofloxacin intermediate. The invention relates to the field of compound synthesis and in particular relates to a method for preparing 3-methylaminopiperidine by 3-pyridinemethaneamine. According to the method, the 3-pyridinemethaneamine is derived, and then pyridine ring is deoxidated by palladium on carbon to obtain the 3-methylaminopiperidine. Compared with the conventional method for directly deoxidating the 3-pyridinemethaneamine, the method uses the palladium on carbon for replacing platinum dioxide for serving as a catalyst so that the cost is greatly reduced so as to be beneficial to mass production.