A differential carrier lifetime (DLT) measurement method with a measurement current as low as 0.1 mA, high noise immunity, and low measurement error has been proposed for the first time for electroluminescent light-emitting diodes (LEDs), which can also obtain the junction capacitance and differential resistance of LEDs. The method is based on the rate equation and phase-sensitive detection technology. The relationship between the DLT of red, green, and blue mini-LEDs and the injected current density was investigated with the proposed method. The DLT of the same LED decreases as the injected current density increases. The DLT of green mini-LEDs drops faster than that of blue mini-LEDs as the injected current density increases.