The invention discloses a multi-target detection and tracking method under conditions of low observability and high clutter, and belongs to the technical field of radar and sonar. The idea of the method is that a plurality of measurements from different propagation paths to a receiver are considered as the possible target measurements during the processing of the target-measurement correlation, and are enabled to be correctly correlated with each known multi-path measurement function, thereby obtaining the accumulation of target information, and improving the target detection capability; and then the target tracking is carried out in a mode of a sliding window. The method employs the target information which is transmitted to a sensor through different paths, enables the measurement information to be correctly correlated with each known multi-path measurement function, thereby obtaining the accumulation of target information, and improving the detection capability of a target under the conditions of the low observability and high clutter. The method can effectively reduce the impact between the adjacent objects.