A data management circuit with network functions and a network-based data management method are provided. The network-based data management method is used to manage a storage device coupled to a computer that includes a processor. The method includes steps of: receiving a network packet through a network; sending the network packet to the processor or accessing the storage device, according to a network header of the network packet; and notifying the processor to access the storage device according to a remaining capacity of the storage device and/or a content of the network packet. The data management circuit with network functions implements a personal cloud system with low cost and low power consumption.