Abstract: In recent years, it has become increasingly difficult for individual passive sonars to detect targets due to the continuous improvement in the stealthiness and mobility of submerged targets. However, distributed multi-sensor fusion technology offers a promising solution. In this study, four decision-level fusion strategies (AND, OR, K/N, and CV) are applied to distributed multiple vertical line arrays for target detection scenarios in deep-ocean environments. Their fusion detection capabilities are analyzed and evaluated based on the passive sonar equation and the energy detection method. The results indicate that AND fusion can effectively reduce the false alarm rate (FAR), but it is accompanied by a significant decrease in detection rate (DR) as the number of vertical line arrays increases. OR fusion can greatly improve the DR, although its false alarm performance heavily depends on that of individual vertical line arrays. The K/N fusion system performs between the above two systems; however, its DR decreases sharply with increasing spacing between vertical line arrays, making it suitable for systems with densely distributed vertical line arrays. As a theoretically optimal fusion strategy, CV fusion achieves a DR and FAR slightly lower than those of OR and AND fusion, with higher detection probability for distant targets compared to K/N fusion. However, its limitation lies in requiring knowledge of the performance parameters of each vertical line array.