test1.tex

\documentclass[a4paper,12pt]{article}
\usepackage[a4paper,landscape,textwidth=50em,tmargin=24mm,bmargin=24mm]{geometry}
\usepackage{calc}
\usepackage[PunctStyle=plain,RubberPunctSkip=false,CJKglue=,CJKecglue=\hskip 4pt plus 20pt]{xeCJK}

\setlength{\parindent}{0pt}
\setlength{\parskip}{7pt}
\pagestyle{empty}

\begin{document}
天地玄黄宇宙洪荒\hrule
xxxxxxxxxxxxxxx\hrule
ddddddddddddddd\hrule
lglglglglglgllg\hrule
\^A\^O lglg\hrule
\LaTeX\hrule

\lineskiplimit=-\maxdimen

\vskip 20pt

天地玄黄宇宙洪荒\hrule
xxxxxxxxxxxxxxx\hrule
ddddddddddddddd\hrule
lglglglglglgllg\hrule
\^A\^O lglg\hrule
\LaTeX\hrule

\end{document}