Abstract: There are some critical nodes in Ad Hoc networks, and the failure of these critical nodes can critically affect the performance of the network. For the aim of selecting the important and trusted critical nodes in Ad Hoc networks, the definition of critical nodes is given, meanwhile, a critical nodes selection algorithm based on trust evaluation is proposed. By using the node contraction, the importance degree of the node is calculated. Then combined with D-S evidence theory, the trust evaluation model of critical node is presented, which is used to obtain the objective trust of the node and to judge the credibility of the node. Finally, the critical nodes are selected by considering of the importance degree and the credibility of the node. Simulation results show that when those critical nodes are failure, selected by the proposed algorithm, the network performance is decreasing significantly.