Abstract: A new method which can ameliorate the accuracy of passive sonar detec-tion system (PSDS) is presented with the conception of optical data fusion. Firstof all, M-unit-sonar-plane-array is divided into correlation 3-unit subsystems. Theexpression of subsystem's detection value and variance of situation are obtainedrespectively. Secondly, the confidence interval of every subsystem is defined withthe conception of error probability and the subsystem detection error is tested andthe support rejection of subsystem is determined. Lastly the optical data fusion algo-rithm for improvement of the detection accuracy is discussed by the computationof 4-unit well-distributed circle PSDS.