Dichomeris mengdana is a moth in the Gelechiidae family. It was described by Li and Zheng in 1997. It is found in China (Qinghai). The wingspan is 19-19.5 mm. The forewings are greyish brown, with scattered greyish white and black scales and with the costal margin fuscous. There are short obscure streaks, as well as an irregular blotch at the base, the middle and the end of the cell. The hindwings are grey with scattered brown scales.