The invention discloses a method for synthesizing aminopyridine and 4-aminopyridine in one step and belongs to the technical field of chemical material synthesis. The method comprises the following steps: in a low temperature condition, carrying out a pre-reaction in a sodium hypochlorite aqueous solution by taking cyanopyridine as a raw material and sodium tungstate as a catalyst (the adding amount of the catalyst is about 2-5% by mass of the raw material cyanopyridine), wherein the reaction is stopped on formamide pyridine; and then raising the temperature for Hoffman one-step reaction to obtain aminopyridine. Taking synthesis of 4-aminopyridine as an example, the reaction condition is easy to control, the reaction step is simple, the product is convenient to operate, side reactions arefew, the product purity can reach 99.95%, and problems of severe pollution, low yield and the like in the prior art are solved.