A method for fuel injection of an engine system may include detecting driving information, including a combustion pressure in a combustion chamber, a heat generation amount in the combustion chamber, a crank angle, and a pressure/temperature/air amount of an intake manifold and an exhaust manifold, setting a fuel amount and injection timing with respect to a pilot injection as map data from an internal temperature, determining whether a maximum combustion pressure change rate is greater than a predetermined pressure change rate, determining generation timing of the maximum combustion pressure change rate, when the maximum combustion pressure change rate is greater than the predetermined pressure change rate, and decreasing a fuel amount of the pilot injection when the maximum combustion pressure change rate is generated during the pilot injection.