To provide novel way for the application of hydrogen-containing carbon (a-C:H) films in methanol engines. First, a-C:H film was prepared on Si substrate by BiP-PECVD method, and then annealed at 500 ℃ in Ar atmosphere for 1 h. The unannealed and annealed a-C:H films were characterized through Nano-indenter, X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared spectroscopy (FTIR), Raman spectroscopy, Field Emission Scanning Electron microscopy(FESEM), CSM tribometer, etc. to obtain its structure, mechanical properties, surface morphology and tribological properties. The effect of annealing at 500 ℃ on the tribological behavior of a-C:H film was comparatively studied in dry air and methanol environment. As a result, after annealed at 500 ℃, the carbon hybridization have been changed from sp3-C to sp2-C resulting in graphitization of the film and the value of C==C/C—C increasing from 0.67 to 0.99. The hardness decreased from 26.5 Gpa to 22.0 GPa and the elastic modulus was almost unchanged as well as the H/E decreases, which means the wear resistance becomes worse in dry air. Compared with the unannealed a-C:H film, in dry air, the friction coefficient of the a-C:H film annealed at 500 ℃ decreased from 0.031 to 0.024, and the wear rate increased by 1.27 times. Meanwhile, the wear volume of both corresponding friction ball reduced from 4.22×10–6 mm3 to 3.99×10–6 mm3; In the methanol environment, the friction coefficient of the a-C:H film annealed at 500 ℃ increased from 0.052 to 0.062), and the wear rate increased by 15.11 times. Meanwhile, the wear volume of the corresponding friction counter ball also increased from 6.16×10–6 mm3 to 13.9×10–6mm3 However, the wear rate of unannealed a-C:H film in methanol environment was 1/2.84 of that in dry environment which shows a decreasing trend; the wear rate of a-C:H film annealed at 500 ℃ in methanol environment was 4.14 times lower than that in dry environment. In a summary, under annealing temperature of 500 ℃, a-C:H film will result in graphitization, which is conducive to tribological properties in dry air but not in the methanol environment.