\documentclass{article}
\makeatletter
\newcounter{Part}
\setcounter{Part}{0}
\def\Part#1{\stepcounter{Part}%
\addtocontents{toc}{\centerline{Part~\thePart. #1}}%
}
\begin{document}
\tableofcontents
\section{Introduction}
\Part{New}
Salam. This is a section\dots m...
\section{salam}
\Part{Another Part}
\section{some section}
salam
\end{document}