A vehicle system includes: an engine including a combustion chamber in which an air-fuel mixture is burned to generate energy, an intake manifold which supplies air to the combustion chamber, an injector which supplies fuel to the combustion chamber, and an exhaust manifold which discharges exhaust gas generated by combustion of the air-fuel mixture through an exhaust pipe; a hybrid starter and generator (HSG) which generates electricity by starting the engine or by using energy generated in the engine; a soot filter which is mounted to the exhaust pipe and collects particulate matters (soot) included in exhaust gas; and a control unit which controls an operation of the injector and controls an operation of the HSG, in which when the quantity of soot is larger than a predetermined quantity, the control unit increases a size of a load of the HSG by a predetermined load quantity until a temperature of the soot filter reaches a predetermined temperature.