This paper presents a systematic investigation of the microstructure and magnetocaloric properties of melt-extracted Sm20Gd20Dy20Co20Al20 high-entropy microwires. The fabricated wires exhibited an amorphous structure, and the temperature interval of the undercooled liquid Delta T was 45 K. The microwires underwent a second-order magnetic transition from a ferromagnetic to a paramagnetic state near the Curie temperature (T-C=52 K). The maximum magnetic entropy change (-Delta S-M(max)), the relative cooling power and the refrigeration capacity reached 6.34 J.kg(-1).K-1, 422.09 J.kg(-1) and 332.94 J.kg(-1), respectively, under a magnetic field change of 5 T. In addition, the temperature-averaged entropy changes with two temperature lifts (3 and 10 K) were 6.32 and 6.27 J.kg(-1).K-1, respectively. The good magnetocaloric performance highlights the significant potential for the Sm20Gd20Dy20Co20Al20 microwires to be used as magnetic refrigerant materials in low-temperature region applications. This work will serve as a valuable reference for future investigations on low-temperature high-entropy magnetocaloric materials.