Compsolechia platiastis is a moth of the Gelechiidae family. It was described by Meyrick in 1922. It is found in Brazil (Amazonas). The wingspan is about 14 mm. The forewings are dark ashy-grey. The plical and first discal stigma are indistinct, cloudy and dark fuscous, the plical rather anterior. There is a slender irregular grey line from four-fifths of the costa to the dorsum before the tornus, margined anteriorly by a broad dark fuscous fascia extending from the dorsum three-fourths across the wing, and posteriorly by a narrow entire fascia. There are two or three cloudy dark fuscous dots on the upper part of the termen. The hindwings are dark fuscous.