Permissive hypercapnia is not limited only to the application of lung protection clinically,it also has a multi-organ protective effect.This review summarizes the multi-organ protective effects and mechanism of permissible hypercapnia.The literature review results found that the protective effects of permissible hypercapnia can reduce apoptosis through anti-inflammation and anti-oxidative stress,and improve tissue oxygenation on lungs and brain by improving mitochondrial structure and myocardial ischemia-reperfusion injury.These findings provide reference for the later study and different clinical applications of permissible hypercapnia.