Paracetamol (APAP) represents a critical emerging contaminant in various water bodies and sulfate radical (SO4 center dot-)-involved Advanced Oxidation Processes (AOPs) using Oxone are proven as promising approaches for degrading APAP. While Co3O4 is the benchmark catalyst for activating Oxone, Co3O4 nanoparticles are usually found to aggregate severely, losing their catalytic activities. In this study, a facile but convenient protocol is developed to prepare a unique Co3O4 material, which exhibits a morphology of nanoflower. More importantly, the flower petals of this Co3O4 nanoflower (CNF) are needle-shaped and comprised of numerous fine Co3O4 particles which are separated, enabling this CNF to exhibit high surface areas and large pore volumes. CNF also shows significantly higher catalytic activities than the commercial Co3O4 NPs for activating Oxone to degrade APAP. APAP degradation is confirmed to involve with sulfate radicals via examining effects of radical probe reagents and EPR analysis. CNF is reusable over several continuous cycles. The APAP degradation pathway is also investigated according to the degradation products determined using LC-MS/MS. The findings of this study are valuable to advance treatments of APAP in water by sulfate-radical-based processes, and also insightful to determine catalytic characteristics of Co3O4 with such a unique morphology of nanoflower.