The invention relates to the technical field of biology, and in particular relates to a nanogold probe. The nanogold probe comprises nanogold particles and a double-chain probe connected to the nanogold particles, wherein the double-chain probe comprises a first chain and a second chain; the first chain comprises a first sector and a second sector which are arranged in sequence in a 5'-3' mode; the first sector and the second chain are complementary; the second sector is used as a sticky tail end and is used for recognizing a target sequence; and the second chain is modified by a fluorescent group. According to the nanogold probe provided by the invention, the nucleotide number of the second sector is adjusted, so that the hybridization efficiency of an identification sequence and the target sequence is regulated and controlled, and then the identification capability of the nanogold probe on the target sequence is regulated and controlled.