Abstract: A multi-function driving power supply system for the organic light emitting device (OLED) was proposed to improve the single function, circuital complexity and high cost of exiting systems. The proposed system was based on a single-chip microcomputer STC89C52 and a character liquid crystal display module LCM1602. This power supply system could flexibly provide four different power sources, i.e, a variable constant voltage source, a variable constant current source, a pulse voltage source and a hybrid current-voltage source (a voltage-controlled constant current source for direct bias and a voltagecontrolled constant voltage source for reverse bias) with adjustable frequency and duty cycle. The output was regulated according to the actual testing condition of an OLED sample. Testing results show that the system was competent for demand of power design, with high stability, high resolution, low ripple quotient and small error. Meanwhile, the system had characteristics of simple structure, convenient operation, easy expansion and low cost.