  In the Framework of {\it{valon model}} we have calculated the parton
distribution in a valon for both the polarized and unpolarized cases. These
distributions are originated purely from the dressing of a valence quark in QCD
and are common to all hadrons. Structure functions, $F_{2}^{p,\pi}$, are
obtained, which agree rather well with the experimental results. A simple
relation between $F_{2}^{p}$ and $F_{2}^{\pi}$ is inferred. For the polarized
structure function, $g_{1}$ while the model gives good agreement with data, it
requires a sizable angular momentum contribution to the spin of the valon, and
hence to that of proton. This contribution is calculated.

High Energy Physics - Phenomenology