  We present the analysis of cloud-cloud collision (CCC) process in the
Galactic molecular complex S235. Our new CO observations performed with the
PMO-13.7m telescope reveal two molecular clouds, namely the S235-Main and the
S235-ABC, with $\sim$ 4 km s$^{-1}$ velocity separation. The bridge feature,
the possible colliding interface and the complementary distribution of the two
clouds are significant observational signatures of cloud-cloud collision in
S235. The most direct evidence of cloud-cloud collision process in S235 is that
the S235-Main (in a distance of 1547$^{+44}_{-43}$ pc) and S235-ABC
(1567$^{+33}_{-39}$ pc) meet at almost the same position (within 1$\sigma$
error range) at a supersonic relative speed. We identified ten $^{13}$CO clumps
from PMO-13.7m observations, 22 dust cores from the archival SCUBA-2 data, and
550 YSOs from NIR-MIR data. 63$\%$ of total YSOs are clustering in seven MST
groups (M1$-$M7). The tight association between the YSO groups (M1 $\&$ M7) and
the bridge feature suggests that the CCC process triggers star formation there.
The collisional impact subregion (the South) shows $3\sim5$ times higher CFE
and SFE (average value of 12.3$\%$ and 10.6$\%$, respectively) than the
non-collisional impact subregion (2.4$\%$ and 2.6$\%$, respectively),
suggesting that the CCC process may have enhanced the CFE and SFE of the clouds
compared to those without collision influence.
