Abstract: The effects of crop rotation of pineapples-sugarcane on sugarcane growth and soil microflora were studied. The results show that both of the sugarcane yield and sucroser content of cane in the crop rotation of pineapple-sugarcane are higher than those of the continuous cropping of sugarcane-sugarcane. Compared with other fields, the crop rotation field can improve the capability of aeration and water storage, accelerate the release of the quick effective nutrient, strengthen soil enzyme activity and increase the total quantity of microbe of soil. The beneficial ammonifier and the nitrifying bacteria double increase, while the unbeneficial anaerobic bacteria and denitrifying bacteria are inhibited.