Abstract:In this paper Chrysanthemum morifolium fields were planted continuously for 1, 3, 7 and 15 years were selected and the output of C. morifolium, disease incidence, elements in the soil and plants, the culturable microbes, phenolic acids in the soil and their effects on the growth of C. morifolium were studied. The results showed that output decreased gradually and disease incidence increased gradually. The flower yield for continuous cropping 15 years was 19.80% of one year’s. Disease incidence reached to 100% for continuous cropping 15 years. The content of soil boron decreased with the increasing years of C. morifolium continuous cropping, while other elements including nitrogen, phosphorus, potassium, iron, manganece, copper and zinc did not change significantly. All the above eight element of plant in the continuous cropping 15 years were decreased significantly than those of other cropping years. Fungi colony forming unit (CFU) of soil increased significantly with the increasing of cropping years. CFU of bacteria and actinomycete reached to highest in 3 year cropping field, but decreased significantly in 15 year cropping field, which indicated a shift of soil microflora from bacteria type to fungi type. The content of p-coumaric acid in soil increased with the increasing cropping years and coumarins appeared in 7 year cropping soil. The biomass and root of C. morifolium were not affected by low content of p-hydroxybenzoic acid, vanillic acid and p-coumaric acid, but they were significantly inhibited by coumarins, mixed phenolic acids and high concentration of p-coumaric acid. The continuous cropping obstacles of C. morifolium may be related to phenolic acids accumulation, microflora’s changes and the lack of microelement B, which affected the microenvironment and the growth of C. morifolium.