This article presents an active electro-optic (EO) modulation electromagnetic pulse (EMP) sensor powered by laser. The sensor simulation model is established, and the temporal response characteristics of the sensor are analyzed based on finite element method (FEM). The laser powered supply circuit and receiving modulation circuit are designed and implemented. A monopole antenna is designed and used to revive the EMP. By integrating the supply circuit, the receiving modulation circuit and the antenna together, the sensor is finally fabricated and encapsulated. Experimental results indicate that with the designed laser powered supply circuit, the sensor can operate continuously and stably. The measured standard 1.2/50 μs lightning electromagnetic pulse (LEMP) in the time domain agrees well with the input LEMP voltage waveform. The linear maximum and minimum measurable electric fields of the sensor are 20.8 kV/m and 221 V/m, respectively. All the results demonstrate that the sensor can provide an effective technical means for the measurement of EMP in the time domain.