\documentclass[12pt]{standalone}

\usepackage{tikz}
\usepackage{ctex}

\usetikzlibrary{shapes.geometric}
\usetikzlibrary{positioning}

\tikzset{flowchart node/.style={draw, minimum height=1cm,
    minimum width=2cm}}
\tikzset{startstop/.style={flowchart node, rectangle, rounded corners}}
\tikzset{start/.style={startstop}}
\tikzset{stop/.style={startstop}}
\tikzset{process/.style={flowchart node, rectangle}}
\tikzset{decision/.style={flowchart node, diamond, aspect=1.5}}

\begin{document}
\begin{tikzpicture}

\node[start] (init) {初始化};
\node[decision, right=1cm of init] (condition) {判断条件成立};
\node[process, above=1cm of condition] (body) {循环体};
\node[stop, below=1cm of condition] (end) {结束};

\draw[->] (init) -- (condition);
\draw[->] (body) -- (condition);
\draw[->] (condition.east)
    -- ++(1cm,0) |- node[right, pos=0.25] {是} (body);
\draw[->] (condition) -- node[right] {否} (end);

\end{tikzpicture}
\end{document}
