The grain sorghum inbred line 654 serves as a parent for numerous Chinese commercial hybrids and recombinant inbred lines (RILs), which have played a pivotal role in the cloning of several agronomically important traits. In this study, we present a telomere-to-telomere (T2T) genome assembly of the inbred line 654 (728.81 Mb) using PacBio HiFi, ultra-long Oxford Nanopore Technology, and Hi-C sequencing data. The T2T genome assembly has high integrity (contains all of 10 centromeres and 20 telomeres without any gaps), high contiguity (contig N90: 52.02 Mb), high completeness (98.33% BUSCO completeness, 98.88% k-mer completeness, and LAI 24.38), and extremely low base error (3.37 × 10-7, QV: 64.72). A total of 62.34% sequences were identified as repetitive, and rest region contained 44,399 protein-coding genes, of which 30,245 were functionally annotated. The gap-free T2T genome assembly enables the full picture of the potential translational genomics, and provides the highest resolution genetic map for future studies on genome evolution, structure variation, and the genetic control of agronomic traits in sorghum breeding.