According to the GB/T17626． 11—2008 and the correlated research results at home and abroad，an ex-perimental scheme was proposed to explore the tripping characteristics of low-voltage release under voltage sag，and the corresponding experimental platform was constructed． With this platform，large-scale experiments of 10 com-monly-used low-voltage releases were carried out at different voltage sag amplitudes，durations and phases，finding that the amplitude，the duration and the phase collectively determine the tripping characteristicsof low-voltage re-lease under voltage sag． Moreover，the experimental results were extremely treated and a curve fitting was per-formed to explore the function relationship between the amplitude and the duration at different phases，as well as the function relationship between the phase and the duration at different amplitudes． Thus，a tripping model of low-voltage release under voltage sag is successfully established．