A reminding apparatus includes: a reminding module, configured to determine reminding time of the reminding apparatus and a reminding event corresponding to the reminding time, and trigger the reminding event when the reminding time is up; a background miming module, configured to indicate an operation system of the data processing device to trigger the reminding apparatus to enter a background running state after detecting a switch instruction; a battery level checking module, configured to check battery level of the data processing device when the reminding apparatus runs in the background; and a battery level protecting module, configured to write a local notification into the operation system when the battery level is lower than a predefined threshold, set triggering time of the local notification as the reminding time, and trigger the reminding apparatus to enter a pending state. The local notification can be triggered automatically by the operation system.