The invention discloses a three-phase electric energy meter based on wide-area synchronous measurement. The three-phase electric energy meter comprises a central processor, a synchronous measurement electric energy metering module, a memory, a constant temperature crystal oscillator and a clock chip, and the synchronous measurement electric energy metering module, the memory, the constant temperature crystal oscillator and the clock chip are connected with the central processor; the central processor is used for externally being connected with a clock synchronization system, a second pulse of which is a benchmark, or an IEEE 1588 protocol clock system and for checking and keeping the time with the clock system, and the central processor is also used for sending an automatic synchronization sampling command to the synchronous measurement electric energy metering module and processing sampled data; the synchronous measurement electric energy metering module is used for metering electric energy and for synchronously collecting a plurality of continuous voltage current instantaneous data of each path in a whole net and storing the continuous voltage current instantaneous data; the memory is used for storing data processed by the central processor; the constant temperature crystal oscillator is used for cooperation with the central processor to carry out time keeping; and the clock chip is used for providing a work clock for the central processor. The invention further discloses a measurement method of the three-phase electric energy meter based on the wide-area synchronous measurement. Instantaneous values of electrical parameters can be synchronously measured, and requirements of the wide area measurement can be met.