Boron-doped micro-nanocrystalline diamond coating may be successfully prepared on Mo substrate with DC arc plasmas jet deposition device. Along with the increase of doped-boron concentration in the film, two-point resistance measurement indicates that film resistance presents exponential decrease; Raman spectrum test shows that, the characteristic peak value of diamond 1332cm-1 in the spectrum moves toward low frequency, the semi-height width of diamond peak, peak D and peak G, etc. in the spectrum is expanded, and the component of non-diamond bonds such as sp2, etc. in the film is increased; SEM and AFM observation shows that, increasing the doped-boron concentration could further subdivide the crystal grains in the film, and is beneficial for the growth of nano- or ultra-nano-crystalline diamond film; film annealing test shows that, micro-nanocrystalline diamond film with higher doped-boron concentration has better thermal stability than the micro-nanocrystalline diamond film without doped boron.