You should always post complete, compiliable examples. No one enjoys guessing what packages you're using.
You could use either \scalebox from
graphicx or \psscalebox from pstricks (which you seem already to be using).
For example, to scale to 50% of the original size:
Code: Select all
\documentclass{article}
\usepackage{pst-plot,pst-text}
\begin{document}
\begin{figure}[!htb]
\psscalebox{0.5}{%
\begin{pspicture}(-5,-5)(10,10)
\psaxes[linewidth=1.2pt, labels=all]{->}(0,0)(-5,-5)(10,10)
\pscurve[showpoints=true](-5,-5)(1,0.25)(5,9)(10,10)
\end{pspicture}}
\end{figure}
\end{document}