  We study the relation between accretion, black hole mass and jet power in
AGN, by using a large group of blazars detected by the Fermi Large Area
Telescope and radio galaxies. Our main results are as follows. (i) The jet
power of FSRQs and FRII-HEG depends on the black hole mass, which suggests that
the FSRQs and FRII-HEG are in Radiation-Pressure Dominated regime. The jet
power of BL Lacs and FRI-LEG depends on the accretion, which suggests that the
BL Lacs and FRI-LEG are in the Gas-Pressure Dominated regime. (ii) We find that
most of FSRQs and BL Lacs have $\rm{P_{jet}>L_{BZ}^{max}}$, which suggests that
the Blandford-Znajek mechanism is insufficient to explain the jet power of
these objects. (iii) The FSRQs are roughly separated from BL Lacs by the
Ledlow-Owen's dividing line in the $\rm{\log P_{jet}-\log M}$ plane, which
supports the unified scheme of AGN. (iv) The FSRQs and BL Lacs have a clear
division at $\rm{L_{bol}/L_{Edd}\sim0.01}$, and the distribution of Eddington
ratios of BL Lacs and FSRQs exhibits a bimodal nature, which imply that the
accretion mode of FSRQs may be different from that of BL Lacs. (v) We find a
significant correlation between broad line luminosity and jet power, which
supports a direct tight connection between jet power and accretion.
