\usepackage{amsmath}
\usepackage{lineno}
\makeatletter
\begin{document}
\pagewiselinenumbers
式子前加上\begin{linenomath*}
后加上\end{linenomath*}

signal processing模板给出的例子，也可以\linenumbers

%%The lineno packages adds line numbers. Start line numbering with
%% \begin{linenumbers}, end it with \end{linenumbers}. Or switch it on
%% for the whole article with \linenumbers after \end{frontmatter}.