A network data sharing system includes a service device configured to access a network and at least one handheld electronic device configured to play data. The service device includes a service computing unit configured to encode data and a service transmission module for accessing a network. The handheld electronic device includes a terminal computing unit configured to decode data, a screen and a terminal transmission interface. When the handheld electronic device is connected to the service device through the terminal transmission interface, the handheld electronic device is configured to instruct the service device to access multimedia data on the network, the service computing unit is configured to encode the accessed multimedia data into encoded multimedia data, which the terminal computing unit of the handheld electronic device is configured to decode, and the handheld electronic device is configured to play, or display through the screen, the decoded multimedia data.