Si doped CVD diamond films are prepared on Si substrate by means of hot filament chemical vapor deposition (HFCVD) through adding tetraethoxysilane (TEOS) into acetone as source of reactant gas during the growth process.The samples of diamond films are investigated by scanning electron micrograph (SEM), Raman spectrum, X-ray diffractometry (XRD) and surface profiler.The experimental results show that compared with pure diamond film, Si doped CVD diamond film exhibits grain refinement and smoother surface.Then selective area deposition (SAD) of B-doped diamond films are achieved on both Si doped CVD diamond film and pure CVD diamond film with silicon dioxide layer as sacrificial layer.SEM investigation demonstrates that the boundary of patterning on pure diamond film is rather fuzzy while on pure diamond film it is trim and distinct, which is mainly attributed to the relatively low surface roughness.