The present invention discloses a high-precision measurement data sampling synchronization device and method for a smart grid sensing device. The device comprises a central processing unit, a sampling data buffer, a sampling data counter, a high-precision analog-digital converter, a global positioning system and a crystal oscillator. The sampling data buffer is connected with the high-precision analog-digital converter, the crystal oscillator, the central processing unit and the sampling data counter, the sampling data counter is connected with the global positioning system and the central processing unit, and the central processing unit is connected with the crystal oscillator. The high-precision measurement data sampling synchronization device and method for a smart grid sensing device are able to perform periodic timing adjustment of local high-speed sampling data through adoption of the second pulse information of the global positioning system so as to ensure the accuracy and the synchronization of sampling data of the sensing devices installed at each point in the smart grid, and is able to complete fault line selection and positioning of the smart grid through adoption of a global determination algorithm.