To restore the lower safety periods of the existing source location privacy protection algorithms, a source-location privacy protection algorithm in wireless sensor networks(WSNs) based on the ellipse model is proposed. Both the coordinates of the source node and the sink node are used to establish the ellipse model. In order to disperse transmission paths of adjacent packets, the algorithm selects a node randomly on the ellipse as the expected phantom source node, which provides the direction for selecting the phantom source node. Theoretical analysis shows that the probability of the packet away from the source node and the sink node is increased during transmission process by using the proposed algorithm. The experimental results show that the algorithm can enhance the safety period and protect source-location privacy effectively in comparison with the existing source-location privacy protection algorithms.