Abstract: In this paper,data fusion theories and algorithms for distributed parallel detection fusion system are studied. Based on Neyman-Pearson criterion, optimal fusion rule and the decision rule of sensors are presented. An optimized algorithm on the performance of the fusion system is proposed, and applied to the data fusion of distributed multi-radar detection system. Then, the data fusion of three radars with same performance is simulated. The results of the computer simulation show that compared with a single radar, the performance of the fusion system is greatly improved.