Ferromagnetic shape memory alloy Ni-Mn-Ga has large strain output and quick response, which would expect to be an intelligent material applied in actuator and sensor. It’s thermal, mechanical and magnetic properties are very sensitive to the chemical composition. The detail of composition dependence of these properties is reviewed in this paper. The changes of martensitic structure, martensitic transformation temperature and Curie temperature are clarified, the variation tendencies of the magnetocrystalline anisotropy energy and saturation magnetization are summarized, and the mechanism that doping elements reduce the twinning stress of martensite is revealed. Finally, the problems existing in the composition design of Ni-Mn-Ga alloy were discussed.