A range-free algorithm based on mobile sink node and DV-Hop localization scheme is proposed in order to decrease the hardware cost and implement complexity of WSN, the sink node mobiles in the network field based on Gauss - Markov mobility model, and sends location information periodically. Nodes sensing the information will compute the distance between sink and itself based on log-normal distribution model of RSSI. Those nodes who received more than 3 pieces of location information in short distance will be updated as virtual nodes. At last, the algorithm's efficacious and feasible was proved by the simulation experimental results.