Abstract. The central black hole masses of a sample of radio-loud quasars are estimated by using the data of Hβ linewidth and the optical continuum luminosity. The vast majority of the quasars in this sample have black hole masses larger than 108M⊙, while a few quasars may contain relatively smaller black holes. We found a significant anti-correlation between the radio loudness and the central black hole mass. It might imply that the jet formation is governed by the black hole mass.