A data synchronization method, adapted to an electronic apparatus comprising at least a processing unit and a communication unit, the processing unit controlling the communication unit to communicate with a data server and to perform data synchronization with the data server, the method comprising: determining, by the processing unit, whether a data application is switched to be executed in a foreground of a user interface of the electronic apparatus, wherein a data synchronization of the data application is performed with a data server according to a default data synchronization configuration, the default data synchronization configuration being periodical or manual data synchronization instead of based on a push-data notification; and if yes, switching, by the processing unit to perform the data synchronization according to a push-data notification from the data server, wherein the push-data notification is related to an updating data, wherein performing the data synchronization according to the push-data notification from the data server comprises: after the data application is switched from being executed in the background of the user interface of the electronic apparatus to be executed in the foreground of the user interface of the electronic apparatus, performing the data synchronization according to the push-data notification from the data server only once during the data application is executed in the foreground of the user interface of the electronic apparatus; and then switching from performing the data synchronization according to the push-data notification from the data server to perform the data synchronization according to the default data synchronization configuration during the data application is executed in the foreground of the user interface of the electronic apparatus. determining, by the processing unit, whether a data application is switched to be executed in a foreground of a user interface of the electronic apparatus, wherein a data synchronization of the data application is performed with a data server according to a default data synchronization configuration, the default data synchronization configuration being periodical or manual data synchronization instead of based on a push-data notification; and if yes, switching, by the processing unit to perform the data synchronization according to a push-data notification from the data server, wherein the push-data notification is related to an updating data, after the data application is switched from being executed in the background of the user interface of the electronic apparatus to be executed in the foreground of the user interface of the electronic apparatus, performing the data synchronization according to the push-data notification from the data server only once during the data application is executed in the foreground of the user interface of the electronic apparatus; and then switching from performing the data synchronization according to the push-data notification from the data server to perform the data synchronization according to the default data synchronization configuration during the data application is executed in the foreground of the user interface of the electronic apparatus.