\documentclass{article}
\thispagestyle{empty}
\usepackage{graphicx}
\usepackage{pstcol}
\usepackage{color}
\begin{document}

\begin{figure}[bht!]{}
  \begin{minipage}[b]{6cm}
    \centering
\begin{pspicture}(6,6)
\psset{unit=1}
%\psgrid
\psline[linewidth=2pt,arrowlength=5]{->}(3,0)(3,6)
\psline[linewidth=2pt,arrowlength=5]{->}(0,3)(6,3)
\psline[linecolor=red,linewidth=2pt,arrowlength=5]{->}(0,5)(6,2)
\psline[linecolor=red,linewidth=2pt,arrowlength=5]{->}(1.25,0)(4.25,6)
\rput(3.375,5.8){\large $y'$}
\rput(3.5,3.5){\large $y_o$}
\rput[br]{*0}(4.6,5.6){\large $y$}
\rput(5.8,2.7){\large $z'$}
\rput[br]{*0}(5.7,1.8){\large $z$}
\rput(2.2,3.4){\large $\theta$}
%\SpecialCoor
%\psarcn{<->}(4,3){-2}{0}{-26.56}
\end{pspicture}
%\caption{Schematic of the geometric arrangement of solenoid and jet}\label{fig1}
  \end{minipage}%
\end{figure}
\end{document}
