This application provides a data writing method and a storage device. The method is applied to a solid-state storage device SSD, and the method includes: receiving a write command, where the write command carries a type of to-be-written data; determining, based on the type of to-be-written data, a type of storage area that is in an SSD and into which the to-be-written data is written, where the SSD includes a plurality of types of storage areas; determining, based on the type of storage area, a target storage area into which the to-be-written data is written; and writing the to-be-written data into the target storage area. In embodiments of this application, data processing efficiency can be improved.