Developing emerging host materials for constructing high energy-density lithium-sulfur (Li-S) batteries has received extensive attention. Herein, we develop a carbon nanotube (CNT)/S-infilled all-in-one microcapsule for Li-S batteries by catalytically growing CNTs using reduced Co3O4 nanoboxes inside a microcapsule. The encapsulation of Co3O4 nanoboxes into the microcapsule is achieved by using an oil-in-water emulsion. In the all-in-one microcapsule, the CNTs improve the conductivity, the microcapsule shell reduces the loss of polysulfides during cycling, and the void inside the microcapsule efficiently accommodates the volumetric change of sulfur. A Li-S battery based on the all-in-one microcapsule exhibits a high capacity of 1010 mA h g(-1) after 250 cycles and a coulombic efficiency of approximate to 99.8%. Moreover, the battery displays stable performance when cycling at temperatures of -5 degrees C and 45 degrees C, which indicates its good potential for practical applications.