The cult of Mazu, the patroness of sailors, originated as a female village shaman at the end of the 11th century in neighborhood of Putian, near Xinghua, Fujian Province. At the end of the 12th century Mazu got the honoured title of ”princess” and kept it until the first half of 18th century, when the higher title of ”heavenly empress” was bestowed. The form of Mazu figure was altered because of the new title, by varying the head dress and costume. In order to understand the iconography of two early Mazu sculptures at main hall of temples in Southern Taiwan, this research takes the costume of Ming empress and princess as the basis, included the illustration from the books of Mazu legend and stories between the 15th and the 18th century as reference. The analysis has shown several key points: the Mazu sculpture in 'The First Grounded Mazu Temple' in Tainan City could be dated back to the second half of the 17th century Her head dress reflects the typical decoration as auspicious cloud on the middle of the crown with lotus leaves on both sides. Her costume and the style of her accessories continued the traditional manner: the tie band for the apron (bixi) hung under the breast and the rest band descended on the surface layer, down to the ground. The sculpture of Chaotian Mazu at Chaotian Temple in Beigang wears a crown decorated with nine dragons in parallel and two flying phoenixes behind the ears. Such kind of dragon decoration belongs to the empress. Both Mazu sculptures wear the decorated dragon garment in one piece, similarly to caftan, but with band collar. The evident difference by Chaotian Mazu, dated back to the second half of 18th century, is in the description of a sitting dragon in the front above the sea weave with protruded rocks on the apron, whose design patented to the emperor only. Such kind of appearance symbolized Mazu as ”heavenly empress”.