  We predict the effect of the charm structure function on the longitudinal
structure function at small x. In NLO analysis we find that the hard Pomeron
behavior gives a good description of $F_{L}$ and $F^{c}_{k}$ (k = 2,L) at small
x values. We conclude that a direct relation between $F_{L}/F^{c}_{2}$ would
provide useful information on how to measure longitudinal structure function at
high $Q^{2}$ values. Having checked that this model gives a good description of
the data, when compared with other models.
