Popular EDA software such as HSPICE do not have the simulation model of OLED or top-emitting OLED,so it is difficult to design the OLED-on-Silicon pixel driving circuits in microdisplay applications.To solve the problem,the simulation model of top-emitting OLED for microdisplay was studied in this paper.Moreover,three types of equivalent circuit model,which are the single-diode model,the double-diode paralleled model and their equivalent circuits are discussed respectively.Meanwhile,the circuit parameters are got after fitting the I-V curve of the top-emitting OLED,finally all the simulated data from the equivalent circuits by HSPICE and the original I-V curve was compared.The results show that the fitted errors obtained from the diode-connected NMOS model are the smallest one,but its simulated errors are the largest one.The fitted errors and the simulated errors from the single-diode model are relatively large,too.But,smallest fitted errors and simulated errors are got using double-diode paralleled model,and the errors are small enough to satisfy the requirements of designing pixel driving circuits.Finally,the double-diode paralleled model is selected as the SPICE model for top-emitting OLED used in microdisplay.