  We study the N=1/2 supersymmetric theory on noncommutative superspace which
is a deformation of usual superspace. We consider deformed Wess-Zumino model as
an example and show vanishing of vacuum energy, renormalization of
superpotential and nonvanishing of tadpole. We find that the perturbative
effective action has terms which are not written in the star deformation. Also
we consider gauge theory on noncommutative superspace and observe that gauge
group is restricted. We generalize the star deformation to include
noncommutativity between bosonic coordinates and fermionic coordinates.
