Synema Simon, 1864 is a relatively large genus of family Thomisidae Sundevall, 1833 and currently includes 124 species distributed worldwide, except for the Polar Regions. However, Synema can be regarded as being poorly represented in China, with only seven species, three of which are endemic. A new spider species of the genus Synema from Guiyang City in China, is described under the name of S. guiyang J. Zhang, Q. Lu & H. Yu, sp. nov. Detailed descriptions and photographs of the new species are provided. DNA barcodes (a partial fragment of the mitochondrial cytochrome oxidase subunit I gene, COI) of the species were obtained to confirm matching of the sexes and for future use in molecular studies.