Abstract: The Maoshan Group is distributed on the Jiangsu-Zhejiang—Anhui border region. Its age assignment has long been a subject of controversy. After further detailed investigations based on the previous work, the author holds that the contact relationships between the Maoshan Group and the overlying Upper Devonian Wutong Formation and underlying Middle Silurian Wentou Formation are not "disconformable" but rather conformable. Besides, the lower and middle parts of the Maoshan Group contain abundant fish fossils such Sinogaie sp., Siancanthus sp., Anticachi sp. and Xiushuiaspis sp. From the existing data of fish fossils both at home and abroad, the Devonian was a period of flourishing of fishes, while fish fossils are rare in Silurian and still older strata. Therefore, it is advisable to assign the age of the Maoshan Group to Late Silurian-Middle Devonian.