首先在导言区添加subfigure宏包。

\usepackage{subfigure}

整体是双栏排版
需要在单栏插入两个图，并列显示

\begin{figure}[H]
  \centering
    \begin{minipage}[b]{\linewidth}
      \subfigure[]{
        \includegraphics[width=0.46\linewidth]{pictures/strategy (1).pdf}
      }
      \subfigure[]{
        \includegraphics[width=0.46\linewidth]{pictures/strategy (2).pdf}
      }
    \end{minipage}
    \begin{minipage}[b]{\linewidth}
      \subfigure[]{
        \includegraphics[width=0.46\linewidth]{pictures/strategy (3).pdf}
      }
      \subfigure[]{
        \includegraphics[width=0.46\linewidth]{pictures/strategy (4).pdf}
      }
    \end{minipage}
    \caption{xxxxxx.}
    \label{fig:xxxxx}
  \end{figure}

若不想是子图

\begin{figure}[htbp]
	\centering
	\begin{minipage}{0.49\linewidth}
		\centering
		\includegraphics[width=0.9\linewidth]{Figure/chutian.JPG}
		\caption{chutian1}
		\label{chutian1}%文中引用该图片代号
	\end{minipage}
	%\qquad
	\begin{minipage}{0.49\linewidth}
		\centering
		\includegraphics[width=0.9\linewidth]{Figure/chutian.JPG}
		\caption{chutian2}
		\label{chutian2}%文中引用该图片代号
	\end{minipage}
\end{figure}