  We construct a closed form of the action of the supersymmetric $CP^N$ sigma
model on noncommutative superspace in four dimensions. We show that this model
has $\mathcal{N}={1/2}$ supersymmetry and that the transformation law is not
modified. The supersymmetric $CP^N$ sigma model on noncommutative superspace in
two dimensions is obtained by dimensional reducing the model in four
dimensions.
