\documentclass{article}
\usepackage{pstricks-add,pst-plot}
\usepackage{auto-pst-pdf}
\begin{document}
\begin{pspicture}(0,0)(2,2)
\psaxes(0,0)(2,2)
\psplot[linecolor=red]{0}{2}{x}
\end{pspicture}

\end{document}