A projection apparatus, a power management apparatus, and a method for power management thereof are provided. The projection apparatus has a first power socket corresponding to a first power specification and a second power socket corresponding to a second power specification. The second power specification is different from the first power specification. A voltage detection unit is adapted to detect an input voltage received by a powered power socket, wherein the powered power socket is the first power socket or the second power socket. A control unit decides whether the input voltage detected by the voltage detection unit is matched up with the power specification of the corresponding powered power socket to determine an operation mode of the projection apparatus and to determine whether the projection apparatus provides an alarm message to ensure safety of use.