  The study of blazar jet has been performed for several decades via the VLBI
technique, while its generation and propagation stay unclear. In the present
work, we compiled a sample of 407 VLBI detected \textit{Fermi} blazars (VFBs)
and studied the correlations between apparent velocity (${\rm log}\,\beta_{\rm
app}$) and jet/accretion disk properties. We found a positive correlation
between $\gamma$-ray luminosity (${\rm log}\,L_{\rm \gamma}$) and ${\rm
log}\,\beta_{\rm app}$, the correlation suggests that the apparent motion of
jet knot is related to the jet power.
