The plane was owned by Zhuhai Hanxing General Aviation, the Zhuhai municipal maritime bureau said.
All three of the plane's crew members were saved by a rescue team made up of local fishermen, state-run Xinhua news agency quoted the bureau as saying.
The accident was caused by an engine failure, according to an initial investigation.
The plane's crew made a successful emergency landing in the sea after failing to restart the engine, the report said.