The invention relates to a method for precisely and synchronously measuring multiple high and low-potential electric parameters and a device. The device comprises a high potential acquisition and measurement module and a low potential acquisition and measurement module. The high potential acquisition and measurement module is connected with the low potential acquisition and measurement module by an optical fiber. The method includes physically isolating high potential and low potential by the aid of photoelectric transmission technology; obtaining electric parameter data; acquiring data by the aid of the high potential acquisition and measurement module and the low potential acquisition and measurement module; leading the high potential acquisition and measurement module to acquire and record the data; transmitting the waveform data of multiple high-potential electric parameters into the low potential acquisition and measurement module via the optical fiber; recording and storing the waveform data by the low potential acquisition and measurement module; and correcting fixed delay values of the optical fiber, an internal circuit of the high potential acquisition and measurement module and an internal circuit of the low potential acquisition and measurement module to precisely and synchronously measure the waveform data of the multiple high and low-potential electric parameters. The method is novel in conception and is simple, convenient and feasible, the device is reasonable in structure, and the requirement on high precision of high and low-potential electric synchronous measurement can be met.