Through aging experiments, an organic light-emitting diode (OLED) luminance decay model based on a restoration model is proposed to study the lifetime of OLED-on-silicon microdisplays. The luminance decay model is a fusion of the traditional stretched exponential decay and OLED brightness restoration models. The brightness degradation data is used to fit the undetermined parameters in the attenuation model to obtain the qualitative and quantitative relationship between the initial brightness and duty cycle and the life of the OLED to realize the high-precision brightness attenuation prediction of the OLED. Comparing with the measured, it can be concluded that the prediction error of the proposed model is small, and the fitting accuracy is as high as 99.22%. Under the same initial brightness drive, the life prediction accuracy of OLED can be improved by 79.1%. The lifetime performance of OLED-on-silicon microdisplay driven by pulse-width modulation (PWM) is superior to that of traditional current/voltage driven types. At a duty ratio of 12.5%--87.5%, the lifetime of OLED-on-silicon microdisplays can be increased by 1.6--20.9 times.