The burning of straw had a bad effect on the air quality, and increased the prob ability of smoke haze. The smoke haze is a meteorological phenomenon that the ai r is turbid and the visibility range decreases. By using remote sensing data and trajectory of pollutant, and taking the terrain and meteorological condition in to consideration, the meteorological cause of a case of smoke haze on 10 June 20 07 was analyzed. The results show that the decisive factors are the burni ng of straw, stable atmosphere and typical terrain of socalled “Zhengzhou gul f”.