Objective To explore the clinical characterics and pathogenesis of delayed encephalopathy after acute carbon monoxide poisoning(DEACMP)and to discuss the effect of hyperbaric oxgen treatment.Methods A review analysis of 58 DEACMP patients inclu- ding the clinical data such as age range,poisoning degree poisoning appearance etc were made.Results 81% of the 58 DEACMP patients were under low concentration but long-term contact with carbon monoxide,67.2% had in a coma state for over 4 hours,70.7% were over 40 years of age,93.1% did not treat with normal drug and hyperbaric oxygen while 84.2% recuperated health under hyperbaric oxygen treat- ment whose recovery rate of normal behavior was 87.9%.Conclusion DEACMP is closely associated with poisoning appearance,poisoning degree,age and reasonable treatment.Hyperbaric oxygen has a great influence on DEACMP prevention and treatment.