An embodiment of the invention provides a data storage device and data management method thereof. The data storage device is coupled to a host, and includes a storage media having data sectors for storing data and a controller. The controller is coupled to the storage media for sequentially receiving one or more read commands and corresponding one or more logical addresses thereto, reads a plurality of first data sectors from the storage media according to the read commands and the corresponding logical addresses, outputs data of the first data sectors to the host, calculates a valid duration required for the one or more read commands, calculates an average data throughput according to the number of the first data sectors and the valid duration, and determines whether the average data throughput exceeds a predetermined threshold. When the average data throughput exceeds the predetermined threshold, the controller performs a blocking procedure to prevent the storage media from being accessed.