Abstract： Objective To evaluate thestereoacuity before and after operation of Parks shift of neutral zone in congenital nystagmus combined with paralytic strabismus. Methods Using stereograms and near stereo-acuity chart, preoperative measurement of distance and near stereoacuity in primary gaze position and neutral zone were qualitatively and quantitatively determined in 27 congenital nystagmus combined with paralytic stra-bismus. After parks shift of neutral zone, streroacuity measurement was evaluated by the similar method. The grade of stereoacuity before and after operation was analyzed Rusults Nystagmus was disappeared or obviously re-lieved in the primary gaze position, vision was improved 2-5 lines, and compensatory head posture was eliminated or improved after operation in 27 cases. The stereoacuity was gradually improved from 800 to 60 seconds of arc, peripheral to macular stereoacuity, and even foveal stereoacuity. Conclusion Congenital nystagmus combined with paralytic strabismus may partly have stereoscopic vision. The stereoscopic vision in neutral zone may be bet-ter than in non-neutral zone. The nystagmus, compensatory head posture, and distance and near stereoscopic vi-sion were improved after operation of Parks shift of neutral zone.