  The radiative mechanism of the black hole X-ray transients (BHXTs) in their
quiescent states (defined as the 2-10 keV X-ray luminosity $\le 10^{34}{\rm
\,erg\,s^{-1}}$) remains unclear. In this work, we investigate the
quasi-simultaneous quiescent state spectrum (including radio, infrared,
optical, ultraviolet and X-ray) of two BHXTs, A0620--00 and XTE J1118+480. We
find that, these two sources can be well described by a coupled accretion --
jet model. More specifically, most of the emission (radio up-to infrared, and
the X-ray waveband) comes from the collimated relativistic jet. Emission from
hot accretion flow is totally insignificant, and it can only be observed in
mid-infrared (the synchrotron peak). Emission from the outer cold disc is only
evident in UV band. These results are consistent with our previous
investigation on the quiescent state of V404 Cyg, and confirm that the
quiescent state is jet-dominated.
