Directed diffusion protocol enables data-centric routing for smart home sensor network. However, traditional directed diffusion protocol makes all nodes participating in the routing process. This causes a lot of redundant data transmission which brings unnecessary energy consumption. In this paper, we proposed LDDP, a location-based directed diffusion routing protocol for smart home sensor network, which reduces the number of nodes involved in data forwarding by room-based partitioning algorithm. Simulation results show that LDDP has better scalability than traditional DDP. LDDP can save 76^th percentile energy when the node number is 200 and the transmission times is 5000. When the network size is 250, LDDP can also brings 40kb/s network throughput gain than traditional DDP.