This paper presents a precise time synchronization strategy for electric energy data acquire system, which uses hierarchical network method and ensures synchronization accuracy. An improved NTP algorithm is adopted between time synchronization of main station and terminal of electric energy data acquire system, which reduces the influence of uncertain uplink network delay to the synchronization accuracy. This paper also proposes a low-complexity filtering method in reducing the actual implementation complexity, while ensuring the accuracy of time synchronization. Active time compensation is adopted between electric energy meter and terminal of electric energy data acquire system, which uses packets broadcasting through low voltage power line carrier communication. The theoretical analysis and experimental testing proves that the precise time synchronization strategy in this paper can fulfill the accuracy in one second, and is fully able to meet the time synchronization accuracy of the electric energy data acquire system.