671.5 kilometers.

According to Baidu Map query, Hunan Changsha University of Science and Technology is 671.5 kilometers away from Tianhe District, Guangzhou City. It takes 8 hours and 7 minutes to drive via Xuguang Expressway and Guanglian Expressway.

You can also take train G813, get off at Guangzhou South Railway Station, and then take the subway to Tianhe District. The whole journey takes 3 hours and 44 minutes.