Biodegradable mulch films have been developed as a suitable alternative to conventional nondegradable polyethylene films. However, the key factors controlling the degradation speed of biodegradable mulch films in soils remain unclear. Here, we linked changes in the soil microbiome with the degradation rate of a promising biodegradable material poly(butylene adipate-co-terephthalate) (PBAT) in four soil types, a lou soil (LS), a fluvo-aquic soil (CS), a black soil (BS), and a red soil (RS), equivalent to Inceptisols (the first two soils), Mollisols, and Ultisols, using soil microcosms. The PBAT degradation rate differed with the soil type, with PBAT mineralization levels of 16, 9, 0.3, and 0.9% in LS, CS, BS, and RS, respectively, after 120 days. Metagenomic analysis showed that the microbial community in LS was more responsive to PBAT than the other three soils. PBAT hydrolase genes were significantly enriched in LS but were not significantly stimulated by PBAT in CS, BS, or RS. Several members of Proteobacteria were identified as novel potential degraders, and their enrichment extent was significantly positively correlated with PBAT degradation capacity. Overall, our results suggest that soil environments harbored a range of PBAT-degrading bacteria and the enrichment of potential degraders drives the fate of PBAT in the soils.