use \hspace ,eg., \hspace{-.1cm} before and after summation to stop violation of margin. 比如下面一段公式代码 1 \begin{align} 2 \label{sys_1} 3 {\Delta{\ddot {\theta}}}_{i}(t) & = ( -\dfrac{1}{T_{pi}} -\dfrac{k_{pi}}{T_{pi}R_{i}}) {\Delta{\dot {\theta}}}_{i} -