  To investigate the mass dependence of structural transformation and star
formation quenching, we construct three galaxy samples using massive ($M_* >
10^{10} M_{\odot}$) red, green, and blue galaxy populations at $0.5<z<2.5$ in
five 3D--{\it HST}/CANDELS fields. The structural parameters, including
effective radius ($r_{\rm e}$), galaxy compactness ($\Sigma_{1.5}$), and second
order moment of 20\% brightest pixels ($M_{20}$) are found to be correlated
with stellar mass. S\'{e}rsic index ($n$), concentration ($C$), and Gini
coefficient ($G$) seem to be insensitive to stellar mass. The morphological
distinction between blue and red galaxies is found at a fixed mass bin,
suggesting that quenching processes should be accompanied with transformations
of galaxy structure and morphology. Except for $r_e$ and $\Sigma_{1.5}$ at high
mass end, structural parameters of green galaxies are intermediate between red
and blue galaxies in each stellar mass bin at $z < 2$, indicating green
galaxies are at a transitional phase when blue galaxies are being quenched into
quiescent statuses. The similar sizes and compactness for the blue and green
galaxies at high-mass end implies that these galaxies will not appear to be
significantly shrunk until they are completely quenched into red QGs. For the
green galaxies at $0.5<z<1.5$, a morphological transformation sequence of bulge
buildup can be seen as they are gradually shut down their star formation
activities, while a faster morphological transformation is verified for the
green galaxies at $1.5<z<2.5$.
