Provided is a small sized light linear generator system having a two-stroke free piston engine, comprising a cylinder having an induction chamber and a combustion chamber, a motor rack arranged at one end of the cylinder, an outer stator fixed inside the motor rack, an inner stator fixed inside the motor rack and having a gap with the outer stator, a rotor carrying out straight reciprocating motion along the gap formed by the outer stator and the inner stator, a magnet installed upon the rotor, a plurality of helical compressing springs arranged inside the motor rack, used for supporting the reciprocating motion of the rotor, and leading to the resonance motion of the rotor, a piston arranged inside the cylinder, connected with rotor for carrying out reciprocating motion, and compressing the fuel and air inside the combustion chamber, a snifter valve arranged upon the cylinder and used for providing fuel and air for the interior of the induction chamber, an induction flow path communicating the induction chamber and the combustion chamber, and an exhaust port arranged upon the cylinder. With the above technical scheme, the free piston linear generator is likely to operate under resonance state, thereby improving the generating efficiency and output power.