  A comprehensive study of multifrequency correlations can shed light on the
nature of variation for blazars. In this work, we collect the long-term radio,
optical and $\gamma$-ray light curves of PKS 1502+106. After performing the
localized cross-correlation function analysis, we find that correlations
between radio and $\gamma$-ray or $V$ band are beyond the $3\sigma$
significance level. The lag of the $\gamma$-ray relative to 15 GHz is
$-60^{+5}_{-10}$ days, translating to a distance $3.18^{+0.50}_{-0.27}$ parsec
(pc) between them. Within uncertainties, the locations of the $\gamma$-ray and
optical emitting regions are roughly the same, and are away from the jet base
within $1.2$ pc. The derived magnetic field in optical and $\gamma$-ray
emitting regions is about $0.36$ G. The logarithm of $\gamma$-ray flux is
significantly linearly correlated with that of $V$ band fluxes, which can be
explained by the synchrotron self-Compton (SSC) process, the external Compton
(EC) processes, or the combination of them. We find a significant linear
correlation in the plot of $\log\prod$ (polarization degree) versus $\log \nu
F_{\nu}$ at $V$ band, and use the empirical relation $\Pi \sim \sin^n \theta'$
($\theta'$ is the observing angle in the comoving frame blob) to explain it.
The behaviors of color index (generally redder when brighter at the active
state) and $\gamma$-ray spectral index (softer when brighter) could be well
explained by the twisted jet model. These findings suggest that the curvature
effect (mainly due to the change of the viewing angle) is dominant in the
variation phenomena of fluxes, spectral indices, and polarization degrees for
PKS 1502+106.
