Ginger cropping could regulate composition of soil microbial community, but its previous cropping might alleviate or aggregate the effect. To understand the effects of ginger cropping on soil microbial community as affected by its preceding cropping, variations of soil bacterial diversity were studied by analyzing PCR-DGGE fingerprints and DNA sequence in purple soil area of the Minjiang River. Four typical cropping modes (interplanting of corn + sweet potato, mono-cropping of soybean, continuous cropping of ginger, and rice-milk vetch rotation cropping) in this region were selected for the study. PCR-DGGE fingerprints clearly show that cultivation of ginger caused changes in number, position and brightness of DGGE bands, regardless of cropping background of the soil, e.g. reducing richness and Shannon-Wiener index of soil bacteria, and altering structure of the bacterial community. Among the four cropping patterns, the effects were the most significant in the one of continuous cropping of ginger, and the least in the one of interplanting of corn and sweet potato. However, cultivation of gingers made the soils under four different cropping patterns tend to be similar in structure of bacterial community. Sequencing of DGGE bands demonstrates that cultivation of ginger brought about disappearance of Chloroflexi group, and Nitrospira group as well, except for in the soil under the pattern of intercropping of rice-milk vetch, and appearance of bacteria of Brevundimonas in the soil under the pattern of interplanting of corn+sweet potato. The findings help understand the effects of ginger cultivation on soil environment, and provide some scientific basis for optimizing the mode of ginger cultivation.