An air-conditioned mattress comprising:a mat device comprising a first mat configured as a three-dimensional structure made from a plurality of elastic thermoplastic filaments that are randomly tangled with each other, the thermoplastic filaments being fixedly connected at contact portions of the thermoplastic filaments in a way that a plurality of through holes are formed at non-contact portions of the thermoplastic filaments;a cover device covering the mat device and contacting at least a top surface of the first mat, the first mat being more air-permeable than the cover device; andan air-conditioning device disposed inside or outside the mat device and providing hot air flow or cool air flow into the first mat;wherein the first mat has a top surface, a bottom surface, and four lateral surfaces;wherein the cover device comprises a first cover and a second cover; the first cover covers and contacts the top surface, the bottom surface, and the four lateral surfaces of the first mat; wherein the mat device further comprises a second mat which is located under the first mat; the air-conditioning device is disposed in the second mat;wherein the second cover covers the first mat and the second mat, and the second cover covers the first cover.