Abstract: To clarify the molecular characteristics and temporal and spatial expression patterns of soluble starch synthase III-1 gene (MaSSIII-1), using the‘Brazilian’banana pulps as the test material, the MaSSIII-1 gene was cloned by PCR method. Quantitative real-time PCR (qPCR) and Western blot technology were used to analyze MaSSIII- 1 gene and its protein expression pattern. The results showed that the cDNA full-length of MaSSIII-1 gene (accession No. KU757067) was 2397 bp encoding 798 amino acids with four typical domains. The expression level of MaSSIII-1 was low in roots, bulbs, flowers, and bracts, but it exhibited high expression in leaves, peels, and pulps. Moreover, MaSSIII- 1 expression increased gradually with banana fruit development, and then reached the highest expression in 50-60 d after emergence from the pseudostem. The expression level of MaSSIII-1 reached the maximum value in 5 d after harvest and then decreased gradually during postharvest ripening in banana fruit. The expression pattern of MaSSIII-1 protein was consistent with the expression trend at mRNA level during banana fruit development and ripening. These results suggested that the expression of MaSSIII- 1 gene may involve not only amylopectin biosynthesis but also early fruit ripening or amylopectin degradation in banana.