The invention relates to a target localization and tracking system and a method. The system comprises a plurality of cluster localization modules and command control modules, each cluster localizationmodule comprises a plurality of sensor nodes and cluster head nodes, and each cluster head node comprises an initialization module, a particle filtration module, a particle weight calculation module,a re-sampling determination module and an estimation target state module. The method which combines Kalman and particle filtration is adopted for realizing the passive localization of a target, and the computation speed is far lower than the particle filtration method on the basis of realizing high-precision localization; the localization and the track of the target is finally realized by adopting multiple sensors and being based on the observation of the direction of the target, thereby being capable of overcoming the constraint that the traditional machine-mounted or ship-mounted single station system must carry out motorization during the observation period, having no need of observing the motorization of a platform, improving the flexibility of target localization, greatly increasingthe area of a region of target monitoring localization, avoiding the shortcoming of existence of localization blind regions and having very high effectiveness, accuracy and feasibility.