On the basis of the faunas including conodonts Palmatolepis gracilis sigmoidalis, P. gracilis gracilis, Polygnathus germanus, which are found for the first time, and corals Cystophrentis kalaohoensis it is confirmed that the Changjiang Formation refers to the Famennian, and may correlate with the Shaodong Formation and Menggongao Formation of central Hunan. This is the only Devonian deposits known in Hainan Island so far. It means that the outstanding problem of whether the Devonian rocks exist in that island is now settled. Meanwhile, the new evidences indicate that the lectostratotype section of Nanhao Formation of Baoting area refers to the Silurian, rather than the Lower Carboniferous as considered by most geologists formerly. Furthermore, the Member 3 of Nanhao Formation at Shilu-Jinbo district is proved to be the Upper Carboniferous, rather than Tournaisian or Middle-Upper Devonian as deemed to be before.