Abstract. 6LowPAN (IPv6 over Low-power wireless Personal Area Networks) is a low-speed wireless personal area network standard based on IPv6, the key technology of which is IPv6 Routing Protocol for Low-Power and Lossy Networks. In a 6LowPAN network, the network topology is typically dynamically formed, so the RPL routing protocol must be able to discover the connections and select neighbor nodes to establish and maintain the network topology. Aiming at the problem that RPL routing decision can only use single routing metric, fuzzy logic theory is used to introduce multiple routing metrics in routing decision, the objective function is designed and implemented, and the optimal parent node is selected by using the objective function to optimize RPL routing protocol.