The invention discloses a controller area network (CAN) bus gateway, a communication method related with the CAN bus gateway, and a communication system thereof, wherein the communication method applied in the CAN bus gateway comprises the steps of receiving a request which comes from a requesting node of a first CAN network and is used for requesting data from a target node in a second CAN network, wherein the request comprises the identification of the second CAN network and the ID of the target node; analyzing the request for obtaining the identification of the second CAN network and the ID of the target node; and forwarding the request to the target node in the second CAN network based on the obtained identification of the second CAN network and the ID of the target node. Through applying the CAN bus gateway, the communication method and the communication system in a vehicle, even when a certain module in the module requires acquisition for related information of other networks because of a function adding requirement, and variation or modification of the gateway is not required. Furthermore intelligent information forwarding is realized.