A CeO₂ nanodots decorated ketjen black composite was fabricated by a simple wet impregnation method and used as the host of sulfur for a lithium–sulfur battery. The microstructure and chemical components were evaluated by XRD, SEM, TEM, surface area analysis and thermogravimetric analysis. Electrochemical tests and microanalysis demonstrated that CeO₂ nanodots served as the sulfur fixation spots as well as the catalytic agent compared with the reference sample without CeO₂ nanodots. The CeO₂/KB–S cathode material with the CeO₂/KB mass ratio of approximately 15/85 shows a high initial discharge capacity of 905 mA h g⁻¹ at the current rate of 1C and remains at 710 mA h g⁻¹ after 300 cycles. Furthermore, the CeO₂/KB–S cathode shows a promising rate performance with the discharge capacity of 800 mA h g⁻¹ even at the current rate of 2C.