Abstract: To explore the effect of bacterial community diversity of watermelon rhizosphere soil on the occurrence of fusarium, the authors analyzed the rhizosphere bacterial of wilted and healthy plants under both the continuous cropping field soil and rotated cropping field soil. The V4 region of the 16S rRNA gene in bacterial DNA was amplified using the polymerase chain reaction technique, and sequenced by the Illumina Hiseq platform, to conduct a diversity analysis of the soil bacteria microbial community composition of different samples. A total of 234895 tags of high-quality reads were obtained in CH (continuous cropping, healthy), 224092 tags in CW (continuous cropping, wilted), 220963 tags in RH (rotated cropping, healthy), 231746 tags in RW(rotated cropping, wilted), respectively. And the tags were clustered into CH 11230, CW 11228, RH 10068, RW 10248 microbial operational taxonomic units (OTUs). At phylum level, Proteobacteria accounted for the highest ratio in all the four treatments, respectively as RH 55.61% , RW 60.84% , CH 46.06%, CW 47.21%, and the proportion in non-continuous cropping was averagely 11.59% higher than that of continuous cropping. In addition, there was a significant difference between CH and RH, Clostridia was specifically in CH, while Gammaproteobacteria existed only in RH. However, in the genus top 35 bacteria population, the abundance of Mizugakiibacter, Pandoraea, Thermomonas and Acidobacterium in rotate cropping was apparently higher than that in continuous cropping. And Taibaiella, Dyella and Chitinophaga in RH were more abundant compared with other treatments. The results showed that the bacterial community diversity in rhizosphere soil of continuous cropping was higher than that in rotate cropping; the structures of bacterial communities in rhizosphere soil of wilted plants and healthy plants were significantly different under rotate cropping condition; the structures of bacterial community were different under different cultivation conditions. In conclusion, the bacteria community structure, quantity and variety of rhizosphere soil are one of the main environmental factors that affect the occurrence of watermelon wilt.