  Using a unified and systematic scheme, the free field realization of
irreducible representations of osp(2|2) is constructed. By using these
realization, the correlation functions of N=2 super-conformal model based on
osp(2|2) symmetry and free field representation of ${\hat{osp(2|2)}}$
generators are calculated. Free field representation of currents are used to
determine the stress-energy tensor and the central charge of the model.
