  We discuss the origin of superluminal radio jets in Black hole X-ray binaries
with relativistic radio jets in our Galaxy popularly known as microquasars. We
classify the relativistic superluminal jet according to the radio emission in
black hole X-ray binaries (transient or persistent) rather than the mass of the
companion. The black hole X-ray binaries with transient radio emission (mostly
LMXBs) produce superluminal jets with $\beta_{app} >$ 1 when the accretion
rate, $\dot{m}_{accr}$ is high and the bolometric luminosity L$_{bol}$
approaches the Eddington Luminosity, L$_{Edd}$. On the other hand, the black
hole X-ray binaries with persistent radio emission (mostly HMXBs) produce
superluminal jets with $\beta_{app} <$ 1 at relatively low $\dot{m}_{accr}$. We
specially discuss the case of V4641 Sgr, a HMXB with transient radio emission
which produces superluminal radio jets like in LMXBs.
