Sorghum plays an important role in agricultural farming and brewing industry of China. The grain color is one of the important traits， while its genetic basis remains largely unclear. By observing the grain development process using yellow grain material GLB41， we found that on 1 to 16 days after flowering the grain grew rapidly， followed by the slow expansion on 17~24 days， and the coloring on 25 days after flowering. At the coloring stage， the green color gradually faded， the grain color gradually changed from milky white or pale white to light yellow， and then the color deepened， and the grain color changed to dark yellow after 40 days. The genetic locus controlling the yellow grain trait was initially mapped to a 15.6 Mb interval on chromosome 1， and was further delimited between two markers BR13 and P2 by fine mapping in 3215 individuals. The functional annotation suggested seven candidate genes. Through Sanger sequencing of the candidate genes in GLB41 （yellow grain） and 6E16 （white grain）， we found three sequence variations （insertion at 619’- 621’， CTG/Leu； mutation at 819’， Cys to Trp； synonymous mutation at 912’， C to T） at the unreported gene Yellow Seed 2 （Sobic.001G397900）.Therefore， it is speculated that Yellow Seed 2 may be involved in the formation of the grain color of these two parent materials， as a new gene for further deciphering the functional mechanism of grain color in sorghum.