The property parameters of error detectors of DVD optical pickup have important influence on its servo precision and readout signal.This paper introduces usual structure and signaldetecting principle of error detectors,mainly analyses the effect of assembling accuracy of focusing and tracking error detector on the servo properties under DVD and CD modes.In the meantime,this paper presents concrete evaluation formula of property parameters,discusses the measures to check and evaluate the property parameters of error detectors according to actual experimental results,and draws some conclusions useful to actual production and application of DVD optical pickup.