An efficient way to solve the environmental pollution deriving from hydrolyzed polyacrylamide (HPAM)-containing drilling wastewater is urgent. This work adopted a novel method coupling Fenton oxidation with sequencing batch reactor (SBR) to treat gas-field drilling wastewater successively. This Fenton-SBR process reduced COD, HPAM, NH4+-N and total phosphorus (TP) concentrations of drilling wastewater by 98.35%, 87.58%, 94.50% and 93.52%, respectively. While simulated HPAM wastewater with similar HPAM concentration to Fenton-oxidized drilling wastewater was treated only by biological process, and the COD and HPAM removal efficiencies reached 78.26% and 62.95%. The result indicates that the biodegradability of the drilling wastewater was enhanced after Fenton oxidation. Moreover, the analysis on microbial community structure indicates the dominant bacteria in treated drilling wastewater were different from that in treated simulated-wastewater. It can be considered the Fenton-SBR process possesses potential to be applied to treating the drilling wastewater.