Abstract: Using trans2butene and hydrogen as the precursors, 30 μm thick αC:H coating was successfully coated on many (280±50) μm diameter PVAPS mandrels by lowpressure plasma chemical vapor deposition. The surface roughness was measured by atomic force microscopy, the result indicates that the RMS of roughness for 30 μm thick αC:H coating is less than 30 nm. The sphericity and concentricity which were measured by interfere microscope and Xradiography are all better than 99% relatively. Thermogravimetric analysis and Fourier transform infrared spectroscopy spectrum analysis were used to obtain the heat stability and structure of the coatings relatively, and the results show that the films mainly contain sp3 C—H bonds, and the αC:H coating is stability below 250 ℃, but it is turned into graphite when the temperature is 450 ℃.