For the sample from Ge et al. of 87 low-$z$ Palomar--Green (PG) quasi-stellar objects (QSOs) and 130 high-$z$ QSOs ($0<z<5$) with $hb$-based single-epoch supermassive black hole (SMBH) masses, we performed a uniform decomposition of the civ $lambda$1549 broad-line profile. Based on the rest frame defined by the oiii $lambda$5007 narrow emission line, a medium-strong positive correlation is found between the civ blueshift and the luminosity at 5100AA or the Eddington ratio leddR. A medium-strong negative relationship is found between the civ blueshift and civ equivalent width. These results support the postulation where the radiation pressure may be the driver of civ blueshift. There is a medium strong correlation between the mass ratio of civ-based to $hb$-based mbh and the civ blueshift, which indicates that the bias for civ-based mbh is affected by the civ profile.
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