  We establish several non-existence results of positive scalar curvature (PSC)
on fiber bundles. We show under an incompressible condition of the fiber, for
$X^m$ a Cartan-Hadamard manifold or an aspherical manifold when $m=3$, the
fiber bundle over $X^m\#M^m$ ($m\ge 3$) with $K(\pi,1)$ fiber, $NPSC^+$(a
manifold class including enlargeable and Schoen-Yau-Schick ones) fiber, or spin
fiber of non-vanishing Rosenberg index carries no PSC metric, with necessary
dimension and spin compactible condition imposed. Furthermore, we show under a
homotopically nontrivial condition of the fiber, the $S^1$ principle bundle
over a closed 3-manifold admits PSC metric if and only if its base space does.
These partially answer a question of Gromov and extend some previous results of
Hanke, Schick and Zeidler concerning PSC obstruction on fiber bundles.
