Microbial community functional diversity is a sensitive indicator of soil quality; soil management such as different methods of recycling crop straw can affect the microbial community functional diversity of paddy soils. In order to clarify the effects of returning different winter covering crop straw types to the paddy field on the rhizospheric microbial community functional diversity of paddy soils in a double-cropping rice region, this study used different winter covering crops and double-cropping rice patterns as research objectives to analyze the effects of returning five types of winter covering crop straw to the paddy field on the rhizospheric microbial community functional diversity in paddy soils in a small-plot experiment in a paddy field. Five winter covering crops and double-cropping rice combinations were used:ryegrass (Lolium multiflorum L.)-double cropping rice (Ry), Chinese milk vetch (Astragalus sinicus L.)-double cropping rice (Mv), rape (Brassica napus L.)-double cropping rice (Ra), potato (Solanum tuberosum L.)-double cropping rice (Po), and fallow-double cropping rice (CK) as control. In this paper, the average well color development (AWCD) in Biolog-GN plates indicated the capacity for carbon utilization by the rhizospheric microbial community. We analyzed the rhizospheric microbial community functional diversity of the paddy soils with the above five treatments, which was detected using the Biolog-GN system. The results showed that applications of winter covering crop straw returned to the paddy field caused high increases in the AWCD compared with the CK treatment, and the AWCD of Po treatment was greater than those of the Ry and CK treatments at early and late rice maturity stages. It was concluded that applications of winter covering crop straw returned to the paddy field resulted in a change in the carbon utilization efficiency of the rhizospheric soil microbial community. There were differences in the genetic diversity indices of the rhizospheric soil microbial communities among the different recycled straw of winter covering crop treatments at early and late rice maturity stages. The richness, Shannon, and McIntosh indices under different recycled straw of winter covering crop treatments were significantly different, with those of Po treatment the highest and those of CK treatment the lowest, at the early rice maturity stage. The richness, Shannon, and McIntosh indices under different recycled straw of winter covering crop treatments were ordered as follows at the late rice maturity stage:Po > Ra > Mv > Ry > CK. Principal component analysis (PCA) of substrate reactions were analyzed in the present study. The results indicated that there were different carbon substrate utilization patterns among different recycled straw of winter covering crop treatments, and that carbohydrates and amino acids were the main carbon resources in rhizospheric microbe utilization. There were significant differences in carbon substrate utilization patterns in different recycled straw of winter covering crop treatments. Therefore, the application of winter covering crop straw returned to the paddy field could significantly increase the utilization of carbon sources by rhizosphere microorganisms, species richness, and species evenness in double-cropping rice regions.