The invention belongs to the technical field of wireless sensor network communication, and provides an RPL routing method based on bidirectional father node decision. The RPL routing method comprisesthe following steps of: selecting an optimal father node according to routing metrics of all candidate father nodes by a child node; after consulting information is carried through an M-DAO message and the optimal father node receives the M-DAO message transmitted by the child node, judging whether to establish connection with the child node or not according to the information carried in the M-DAOmessage and the current network condition of the optimal father node; and finally, completing networking. According to the RPL routing method, the optimal father node is selected through an optimal father node selection mechanism, so that the probability that the node with heavy link load is selected as the father node is avoided, and meanwhile, a large number of child nodes are prevented from being connected to the node; and secondly, through adopting the bidirectional father node decision mechanism, the data processing capacity of the father node is considered, and the thunder effect causedby the fact that DIO messages cannot finally reflect the connection condition of the node is relieved.