Abstract: Due to the varying quality of probes produced by different manufacturers, the development of electric field standard devices has become particularly important. To meet the calibration requirements of low-frequency, high-field-strength electric field probes, a low-frequency electric field standard device was developed using the parallel plate method. The device consists of two square aluminum plates with a side length of 1 m and a plate spacing of 0.5 m. The frequency range is DC to 10 kHz, with an electric field strength range of 0 to 3000 V/m. Through theoretical analysis, software simulation, and experimental measurements, the effects of edge effects, plate material, structure shape, operating frequency, and other factors on the standard electric field generated by parallel plates were studied, and an uncertainty evaluation was conducted. A new measurement model was proposed, and uncertainty components caused by seven factors were evaluated separately: plate voltage, plate spacing, field uniformity within the parallel plates, probe fixture, probe alignment, finite size of parallel plates, and probe influence. The resulting expanded uncertainty is U=6.8% (k=2). The results show that the developed electric field standard device can meet the calibration requirements for low-frequency electric field probes.