Aiming at the problem that each node has different certainty degree to the target in sensor network with packetdropping, an adaptive weighted fusion based linear distributed filtering algorithm is proposed. Considering the node property and the node influence over the network, node importance and the mutual support degree from observation data are fused by linear weights to attain the certainty degree, and then the fused weights composed by the certainty degree are introduced into the consensus protocol to update the state estimate at each node for the target. The proposed algorithm can not only improve the accuracy of the distributed filtering, but also enhance the consistency of the state estimates. Simulation results demonstrate the effectiveness of the proposed algorithm.