Aiming at the difficult problem oflow slow and small (LSS) targets in complex terrain,this paper analyzes and studies the factors affecting the threat assessment of LSS targets to propose a threat assessment method based on dynamic Bayesian network.Based on the threat attribute of LSS targets,we construct a dynamic Bayesian network topology and deduce the threat value by Bayesian theory. Thesimulation results show that the method based on dynamic Bayesian network is feasible in threat assessment of LSS targets.