A method and a system for cooling a steel strip are disclosed. A high water volume mist cooler and a low water volume mist cooler are disposed along a direction in which the steel strip travels. The high water volume mist cooler sprays high water volume mists onto the surfaces of the steel strip to cool the steel strip, and then the low water volume mist cooler sprays low water volume mists onto the surfaces of the steel strip to cool the steel strip, thereby cooling the steel strip while suppressing the influence of transition boiling, to prevent the steel strip from having a temperature-nonuniform portion.