  We search for the potential contamination in the Planck thermal
Sunyaev-Zeldovich (tSZ) map by calculating the cross-correlation between the
tSZ signal and weak lensing by large scale structure and the Cosmic Microwave
Background (CMB). The lensing data we use is the convergence map from the Red
Sequence Cluster Lensing Survey (RCSLens) and the Planck CMB lensing map. We
reconstruct the tSZ $y$ map with a Needlet Internal Linear Combination method
using the HFI sky maps from the Planck satellite. We remove the CMB signal
while minimizing the residual noise. The cross correlation signal from our
reconstructed $y$ map is consistent with that from the Planck team's NILC $y$
map. The CIB and galactic dust emission are two potential sources of
contamination in the reconstructed $y$ map. We remove the CIB signal by
subtracting the CIB maps reconstructed by Planck collaboration from the raw
temperature maps. We find that cross-correlation between the CIB and galactic
lensing contributes to $(7.5\pm6.0)\%$ in the Planck NILC tSZ cross galactic
lensing signal within $100<\ell<2000$, which implies that previous detections
of the tSZ cross galactic lensing is robust to CIB contaminations. In contrast,
the Planck NILC tSZ cross CMB lensing is biased by $(18.4\pm2.8)\%$ in the same
$\ell$ range. Galactic dust contamination is tested by projecting out a
grey-body dust models with different dust spectral indices. Galactic dust does
not affect galactic lensing cross tSZ signal significantly.

Cosmology and Nongalactic Astrophysics