To satisfy the requirement of field test and special test to high stability of the absolute encoder,technological improvements were made to the traditional absolute encoder processing circuit.In the processing circuitry,A/D converters are used for collecting the amplified and shaped analog signals.The processing to photoelectric signal was implemented through software,including comparison,subdividing,decoding,correcting, averaging, and parameter tuning etc.The actual rotation angle of the shaft angle was converted into natural binary digital code.The practical demonstration projects proved that the encoder system is stable.