Location privacy in wireless sensor networks has gained a wide concern. Particularly, the location privacy of base station requires ultimate protection due to its crucial position in wireless sensor networks. In this paper, we propose an efficient scheme, consisting of anonymous topology discovery and intelligent fake packet injection (IFPI), to protect the location privacy of base station. Anonymous topology discovery eliminates the potential threats against base station within topology discovery period. On the other hand, IFPI enhances privacy protection strength during data transmission period. Under given conditions, comprehensive simulations demonstrate that our scheme significantly improves privacy strength compared with existing strategies.