Abstract: The variations of soil temperature,enzyme activity,contents of chlorophyll(CHL)and malondialdehyde(MDA)in flue-cured tobacco under four mulching methods were studied.The results indicate that the soil temperature at the depth of 5cm and 10cm mulched by straw is lower than that mulched by film during the whole period.Compared with other three treatments of mulching film during the whole period,mulching straw on the ridge during the whole period,and picking-up film and then earthing-up during the blooming period,the treatment of picking-up film,earthing-up during the blooming period,then mulching straw on the ridge has a higher soil temperature at the beginning of planting,and a lower soil te mperature after straw mulching.Also its content of CHL,activities of peroxidase(POD)and nitrate reductase(NR)are higher;content of MDA is lower;and its yield,average price,value and percentage of superior leaves are higher than those of other treatments