The test of the lifetime of organic light-emitting devices(OLED) is important to OLED production.This paper introduces a kind of automatic test system of the lifetime of OLED.It can test 16 OLED panels at the same time.The high-sensitive digital collection circuit can detect the voltage change less than 0.3 mV.For the observed result is recorded by PC automatically,the data are more accurate.Further by using photodiode to replace the luminometer,the cost of the system is reduced.