The cause for the carbon monoxide poisoning and the meteorological influence in Yanji during February 13?4,2006 are analyzed.The results indicate that,both the dura-tive breeze and the obvious rising of temperature are the main meteorological factors for the CO poisoning.In the meantime,weather conditions,such as temperature inversion,weak pressure field,cloudiness etc. ,constrain the surface wind and turbulence for longtime.The time of unfavorable weather factor influence is extended.Most of the people who died in the accident and most sufferers live in narrow and small building,heat preservation and poor ventilation.When influenced by same meteorological conditions,poor ventilation and oxygen supply in these houses worse than normal cause CO to increase prominently in the combus-tion process and unable to discharge normally.This is the basic cause for the accident.