GeC coatings with different refractive index, DLC coatings and dual band IR protective coatings are deposited onto Ge substrates by means of magnetron sputtering. The IR transmittance and micro hardness are investigated by Fourier transform infrared spectroscopy (FTIR) and micro hardness meter, respectively. The hardness of the samples is enhanced obviously by GeC, DLC and the dual band IR protective coatings. Furthermore, the dual band IR protective coatings have high transmittance of larger than 94% in both 3.7~4.8 μm and 7.5~10.5 μm range, and also have greater hardness than both GeC and DLC samples. The dual band IR protective coatings pass the environmental testing according to GJB2485-95.