Matlab/Simulink, Chemkin as well as the finite element method (FEM) have been used to investigate the performance of the novel development of HCCI free piston linear alternator (FPLA). The motion differences between the FPLA and the internal combustion engine (ICE) were also presented. The effects of various resistance loads and equivalence ratios were studied. The simulation results showed that the FPLA has a build-up nature to change the top dead center (TDC) according to loads and other parameters. The high compression ratio could be achieved easily, which is an effective way to reduce the emissions and increase the thermal efficiency.