A fuel amount distribution method is provided to distribute fuel to a plurality of injectors on each of multiple cylinders of an engine with a dual injector. The fuel amount distribution method includes performing, by a controller, a single injection operation in which a single injector of the plurality of injectors constituting the dual injector injects fuel into a corresponding cylinder when a required fuel injection time of the dual injector of at least one cylinder of the multiple cylinders is less than a minimum injection time of each injector of the plurality of injectors of the dual injector. Thereby, precise air-fuel control in a low fuel rate section is achieved.