In order to reveal characteristics of the origin and causes of diffusion of cobalt (Co) materials used in early Ming Dynasty blue-and-white porcelains, four blue-and-white porcelain shards from the early Ming Dynasty and five blue-and-white shards made in Western Asia were analyzed by energy-dispersive X-ray fluorescence (EDXRF) and laser-induced breakdown spectrometry (LIBS). The results showed that the cobalt materials used for early Ming Dynasty porcelains in Jingdezhen are very similar to those for Western Asia blue decoration in glazes, in that both are boron (B)-containing and low-manganese (Mn) cobalt materials. This work reveals not only the relationship between the cobalt materials used in early Ming Dynasty blue-and-white porcelains and Islamic Blue decoration materials from a new perspective, but also that the cause of diffusion of cobalt materials used in early Ming Dynasty blue-and-white porcelains is the pre-fused borax cobalt glass materials which have high sodium (Na) and calcium (Ca) but low aluminum (Al) and silicon (Si) contents. This work may provide an important reference for further studies on the origins of cobalt materials used in blue-and-white porcelains of the Yuan and Ming Dynasties.