The invention discloses a method and device for carrying out automatic matching on field bus terminals, and the device is characterized in that each field communication node is provided with a first communication connector and a second communication connector, wherein the first and second communication connectors are used for constituting a fieldbus network for communication; the first and second communication connectors are respectively connected with a first communication cable connector and a second communication cable connector, and the first and second communication connectors are further connected in series with a terminal feature resistor and a relay, wherein the relay is used for controlling whether the terminal feature resistor accesses a loop. In the invention, a set of auxiliary circuits for monitoring whether communication ports are used is arranged in each communication node, and the feature resistor which is controlled to access by the relay is arranged in the communication node. In such a way, the communication node can logically judge whether to access the terminal feature resistor according to the used information of the two communication ports of the node, so that the automatic matching of terminal feature resistors in the fieldbus network is achieved, therefore, the method and device disclosed by the invention are effective for providing the reliability and usability of a network.