How can I do it?

• Welcome to TeX.SX! Please help us help you and add a minimal working example (MWE) that illustrates your problem. Reproducing the problem and finding out what the issue is will be much easier when we see compilable code, starting with \documentclass{...} and ending with \end{document}. – egreg Jun 13 '15 at 20:15

Use the plain option for the frame:

\documentclass[ ]{beamer}
\usetheme{Singapore}

\begin{document}

\begin{frame}[plain]
\tableofcontents
\end{frame}

\section{A test section}
\begin{frame}test \end{frame}
\section{Another test section}
\begin{frame}test \end{frame}

\end{document}


The result, showing the frame with the ToC and a regular frame: