Anaerobic co-digestion (AcoD) is proved as an effective approach to solving a bottleneck problem of the low biogas yield in agricultural biomass waste treatment with anaerobic digestion (AD) technology. The present study investigated the effect of C/N radio, organic loading rate (OLR) and total solids (TS) contents on reactor performance in AcoD of pig manure and corn straw for simultaneous biogas and biogas slurry production. It was found that the highest biogas production was obtained at C/N ratio of 25, while the best biogas slurry performance was achieved at C/N ratio of 35. And high OLR and TS resulted in good performances in both biogas production and biogas slurry. At last, the microbial community analysis suggested that Bacteroidetes played a significant role in AcoD process. Acetoclastic methanogenesis was the main pathway for methane production in the stable system. And changing operational parameters could transform and shift the microbial community.