Abstract: In the pattern of distributive radar data processing,a target is tracked and estimated by sensors,so various filtered states from the measurements that origin the same target should be fused in order to obtain the more accurate state and flight track of the target.Considering the elements of the estimator's state are different in real scenario,their attributions to the fused state will be different.A fusion rule of linear combination that make the matrix trace of error of mean root be minimized is presented in the paper,and the algorithm of calculation of weight matrix is also driven based on the Lagrange multiplier method.Finally the testing results show that the fused track approaches to the real track.This means that the quality of intelligence can be improved by the method.