In order to solve the problem of passive tracking low-altitude maneuvering target with acoustic network, a Digraph Switch Variable Structure Multiple Model (DS-VSMM) algorithm is proposed. First, acoustic sensors are networked and their time-delay bearing data is aligned, which improves the fusion performance of acoustic network. Second, a variable structure multi-model algorithm is used to estimate target state, in which the weight of new activated model is assigned by digraph switch method. Third, the system output is fused by multiple parallel models. Compared with the IMM method in simulation, the proposed algorithm can match actual target trajectory with less computational complexity and better accuracy.