Abstract: The influence factors on Trilateration are studied for the reason that traditional self-localization algorithms are not suitable for the networked munitions in quality and complexity. According to the error equation deduced, it showed that the errors was due to the common influence of node geometric relation and ranging errors. Geometric influential element and distance offset of localization were presented to describe the influence effect. And they were used to evaluate and screen groups of anchor nodes. Final position was calculated by weighting. Simulation shows that the algorithm can improve the precision through minimizing the unfavorable factors, has better robustness and nice performance no matter the munition nodes are deployed densely or loosely.