  We investigate systematically four outbursts of black hole system GX 339-4
observed by the Rossi X-ray Timing Explorer (RXTE) in both spectral and timing
domains and find that these outbursts have some common properties although they
experience different 'q' tracks in the hardness-intensity diagram (HID). While
the spectral indices are around 1.5 in low hard state (LHS), 2.4 in soft
intermediate state (SIMS) and high soft state (HSS), the spectral parameters of
thermal, non-thermal and reflection components vary significantly in
transitions from LHS to HIMS. Also the quasi periodic oscillation (QPO) shows a
peculiar behavior during the state transition between LHS and HIMS: the RMS
drop of type C fundamental QPO is accompanied with showing-up of the second
harmonic. Interestingly, the QPO RMS is found to have a similar linear
relationship with the non-thermal fraction of emission in different outbursts.
These findings provide more clues to our understanding the outburst of the
black hole X-ray binary system.
