Abstract: Aiming at the data association problem of multiple target tracking in passive sensor array,a novel data association algorithm based on line-of-sight range is proposed for the low probability of target detection environment.Firstly,the disadvantages of the conventional line-of-sight range data association method are analyzed.In order to deal with these disadvantages,the criterion that the average of line-of-sight range of the same target may be the shortest is proposed.At the same time,when the number of measurements of the same target exceeds 2/3 of sensor stations,the association is regarded as valid.Secondly,the fuzzy membership function based on the average of line-of-sight range and the number of valid sensors is designed.Finally,the data association algorithm is built.The simulation results show that the proposed algorithm is more accurate than the existing one for multiple target environments.