On December 6, 2021 a Hapalomys specimen was collected at Mt. Nanling in Guangdong Province (113°00′11.87″ E, 24°56′17.57″ N, altitude 1 023 m). We conducted external and cranial measurements and compared them with those of congeneric species. We sequenced the full-length mitochondrial CYTB gene and constructed a phylogenetic tree using the maximum likelihood method. The specimen has nails on both the thumb and the hallux; the first upper molar has three columns of cusps, each column with three main cusps, which are characteristic of the genus Hapalomys. The absence of two small cusplets between the three main cusps on the anterior margin of the first upper molar, and a tail length nearly equal to the head and body length, are consistent with the features of Hapalomys delacouri. The mitochondrial CYTB phylogenetic tree also showed that this specimen clustered with the Hapalomys delacouri sequences obtained from GenBank, with a bootstrap support of 100%. Collectively, these findings confirm that the specimen belongs to Hapalomys delacouri, representing its first distribution record in Guangdong.