Abstract: In this paper, MnO₂-polydopamine (PDA)/polyvinyl alcohol (PVA) and MnO₂-PVA-5-fluorouracil (5-Fu)/PVA composite microspheres were prepared by electrospinning. Specifically, dopamine (DA) and KMnO₄ were added to the PVA solution, where a redox reaction happened between DA and KMnO₄ to form PDA and MnO₂. Thus, the MnO₂-PDA/PVA microspheres were prepared by electrospinning the MnO₂-PDA/PVA solution. MnO₂-PDA-5-Fu/PVA microspheres were prepared by electrospinning the MnO₂-PDA-5-Fu/PVA solution, which was prepared by directly dissolving 5-Fu in the MnO₂-PDA/PVA solution. The water stability of the electrospun microspheres was given by a glutaraldehyde crosslinking method. The composite microspheres have excellent photothermal conversion, controlled drug release and good biosafety, which were used to prevent the recurrence of tumor after the operation. The photothermal conversion efficiency of MnO₂-PDA-5-Fu/PVA microspheres reaches 24.5% under the irradiation of 808 nm NIR laser, which can achieve the efficient tumor thermal ablation; on the other hand, the released 5-Fu can kill the residual tumor cells after operation. This study confirms the application potential of the microspheres in the field of preventing tumor recurrence, and provides a new strategy for the design of multifunctional composite nanomaterials.