Abstract: To evaluated the dynamics of sporangium diffusion in Tomato Botrytis cinerea and its correlation with disease incidence in greenhouse, observation the dynamic time and space of airborne spores of Tomato Gray Mold by trapped the conidium was assayed.The results showed that the diffusion of Botrytis cinerea on the time and space are randomly Sporangium diffusion occurred mainly during daytime and 88.4% of Botrytis cinerea were trapped during 8:00to 20:00.The trapped quantity of Botrytis cinerea increased after10:00and reducedafter 16:00quickly, and the maximum quantity of conidium Trapped occurred between 12:00to 14:00.Our results suggest that the trapped quantity of Botrytis cinereacorrelated with the Disease index of Gray Mold in the greenhouse during mid to late March to late Aprill (R=0.8850, P<0.01) significantly, and it will be benefit for the predict tomato gray mold and select suitable date for control