The invention discloses a system and a method for measuring impulse grounding impedance based on optical transmission and insulation safety. The system comprises an impulse current generator, an impulse voltage divider, a Rogowski coil current transducer, a first optical to electrical converter, a second optical to electrical converter, a first electrical to optical converter, a second electrical to optical converter, a first optical fiber, a second optical fiber and an oscilloscope, and is characterized in that the impulse current generator is connected with the impulse voltage divider, one end of the impulse voltage divider is grounded, the other end of the impulse voltage divider transmits divided voltage to the first electrical to optical converter, the first electrical to optical converter converts the divided voltage into a first optical signal, the first optical signal is transmitted to the first optical to electrical converter through the first optical fiber, the first optical to electrical converter converts the first optical signal into a first electrical signal and sends the first electrical signal to the oscilloscope. The system disclosed by the invention can greatly improve the safety of measuring equipment and the testing personnel, and has functions of long-distance transmission, interference prevention, photoelectric isolation, safety and reliability.