比较算法（英语：Comparison sort）是排序算法的一种，通过一个抽象的内容比较操作（通常是“小于或等于”操作）来确定两个元素中哪个应该放在串行前面。该算法的唯一要求就是操作数满足全序关系：

对于a≤b并且b≤a这种情况，a和b都有可能被排在前面。这时输入的顺序就会决定最后的顺序。

比较排序类似于将未贴标签的砝码用天平将按质量大小进行排序，并且除了用天平测量两个砝码的质量之外不能用其他方法。

A comparison sort is a type of sorting algorithm that only reads the list elements through a single abstract comparison operation (often a "less than or equal to" operator or a three-way comparison) that determines which of two elements should occur first in the final sorted list. The only requirement is that the operator obey two of the properties of a total order: