We conducted analyses of six shards of export blue and white porcelain from the Nan’ao Ⅰ shipwreck. The results of elemental analysis show that two shards were produced at Jingdezhen Kiln and the other four produced at Zhangzhou Kiln. The materials for making the body and glaze of these two kilns are different, but both kilns used the same domestic cobalt for the blue pigment. The results of microstructure analysis show that the manufacturing technology for the blue and white porcelain produced at Zhangzhou Kiln is different from that of Jingdezhen Kiln. Blue pigment of Jingdezhen Kiln concentrates at the junction of glaze and body, while that of Zhangzhou Kiln diffuses in the glaze or in the middle of glaze. Image optical coherence tomography (OCT) shows that the smooth bright spots of blue pigment of Zhangzhou Kiln were caused by opacified glaze and homogeneously diffused pigments. The blue and white porcelain of Zhangzhou Kiln may represent a unique technology different from that used for underglaze blue of Jingdezhen Kiln for example. In addition, the results of thermodilatometry show that the firing temperatures of blue and white porcelain of Jingdezhen and Zhangzhou Kilns were 1 160 ℃ and 1 175 ℃, respectively, quite close and both lower than normal, which indicates that the kiln technologies of the two places were similar at that time.