Where I did wrong?
\begin{table} \begin{center} \begin{tabularx}{\textwidth}{YYYYYYY} \toprule \textbf{Style} & \multicolumn{2}{c}{\textbf{Yarn}} & & \multicolumn{2}{c}{\textbf{Count}} & \textbf{Weight} & \textbf{Thickness} \\ \cmidrule{2-3} \cmidrule{4-5} & Warp & Fill & Ends & Picks & $[g/m^2]$ & $[mm]$\\ \midrule Plain & TR 30S 3L & TR 30S 3L & $4.87$ & $4.87$ & 200 & $0.23$ \\ \bottomrule \end{tabularx} \caption{Caption} \end{center} \end{table} thanks for help!
Here are some suggestions on how you may want to streamline your code:
Use left- and right-clipping of the \cmidrule lines to better;
there's no need to use a center environment because the width of the tabularx environment is set to \textwidth;
don't typeset units of measurement in math italics -- consider using the \si macro of the siunitx package instead;
when using a smaller-than-normal font size for a table, do also consider reducing the amount of intercolumn whitespace: for the table at hand, a combination of \small (instead of \footnotesize) and setting \tabcolsep (the parameter that governs the amount of intercolumn whitespace) to 4pt (default: 6pt) would seem to yield a more-readable table.
The first column may look better if you use l instead of Y as the column type.
\documentclass{article} \usepackage{tabularx,booktabs} \newcolumntype{Y}{>{\centering\arraybackslash}X} \usepackage[per-mode=symbol]{siunitx} % for typesetting scientific units \begin{document} \begin{table} \setlength\tabcolsep{4pt} % default value: 6pt \small % not: "\footnotesize" \begin{tabularx}{\textwidth}{@{} l *{6}{Y} @{}} \toprule \textbf{Style} & \multicolumn{2}{c}{\textbf{Yarn}} & \multicolumn{2}{c}{\textbf{Count}} & \textbf{Weight} & \textbf{Thickness} \\ \cmidrule(lr){2-3} \cmidrule(lr){4-5} & Warp & Fill & Ends & Picks & [\si{\gram\per\meter\squared}] & [\si{\milli\meter}]\\ \midrule Plain & TR 30S 3L & TR 30S 3L & 4.87 & 4.87 & 200 & 0.23 \\ \bottomrule \end{tabularx} \caption{Main Properties of wowen fabric.} \end{table} \end{document} Just for comparison, here's the look of the table that's produced by the code you presented in your answer:
texdoc siunitx in a command window. I find a way that it works!
\begin{table} \begin{center} \begin{footnotesize} \begin{tabularx}{\textwidth}{YYYYYYY} \toprule \textbf{Style} & \multicolumn{2}{c}{\textbf{Yarn}} & \multicolumn{2}{c}{\textbf{Count}} & \textbf{Weight} & \textbf{Thickness} \\ \cmidrule{2-3} \cmidrule{4-5} & Warp & Fill & Ends & Picks & $[g/m^2]$ & $[mm]$\\ \midrule Plain & TR 30S 3L & TR 30S 3L & $4.87$ & $4.87$ & 200 & $0.23$ \\ \bottomrule \end{tabularx} \caption{Main Properties of wowen fabric.} \end{footnotesize} \end{center} \end{table}
c:-)