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Using a high luminosity ($L_{\rm bol} \sim 10^{47.5} - 10^{48.3}$ ergs$^{-1}$), high redshift ($3.2 < z < 3.8$) quasar sample of 19 quasars withoptical and near-infrared spectroscopy, we investigate the reliability of theCIV-based black hole mass estimates ($M_{\rm BH}$). The median logarithm of theCIV- and H$\beta$-based $M_{\rm BH}$ ratios is 0.110 dex with the scatter of0.647 dex. The CIV-to-H$\beta$ BH mass differences are significantly correlatedwith the CIV FWHMs, blueshifts and asymmetries. Corrections of the CIV FWHMusing the blueshift and asymmetry reduce the scatter of the mass differences by$\sim$ 0.04-0.2 dex. Quasars in our sample accrete at the Eddington ratio$R_{\rm EDD}>0.3$ and cover a considerable range of blueshifts, with 18/19 ofthe quasars showing CIV blueshifts (with the median value of 1126 km s$^{-1}$)and 14/19 of the quasars showing CIV blueshifts larger than 500 km s$^{-1}$. Itsuggests that not all quasars with high Eddington ratios show large blueshifts.The Baldwin effect between the CIV rest-frame equivalent width (REW) and thecontinuum luminosity at 1350 $\overset{\lower.5em\circ}{\mathrm{A}}$ is notseen, likely due to the limited luminosity range of our sample. We find a lackof flux in the red wing of the composite spectrum with larger CIV blueshift,and detect a higher ratio of [OIII] quasars with REW$_{\rm [OIII]}>5$$\overset{\lower.5em\circ}{\mathrm{A}}$ in the subsample with lower CIVblueshift. It is more likely that they are caused by the combination of theEddington ratio and the orientation effect.

CIV emission line properties and uncertainties in black hole mass estimates of z ~ 3.5 quasars