A method for clock synchronization of an industrial internet field broadband bus, the method is applicable to an industrial internet field broadband bus architecture system comprising a bus controller and at least one bus terminal, the bus controller is connected with the bus terminal over a two-wire data transfer network, and the method comprises steps of: electing one of the bus controller and the bus terminal as a best master clock; determining whether an IP address of the device of the best master clock is the same as an IP address of the bus controller; if so, then determining the bus controller as a master device of clock synchronization, and transmitting by the bus controller a synchronization message to the bus terminal for clock synchronization; and otherwise, returning to the step of electing one of the bus controller and the bus terminal as the best master clock; characterized in that, the method further comprises: segmenting, by the bus controller, a transmission period of time available over a bus in the two-wire data transfer network into synchronization time slices and data time slices: the transmitting, by the bus controller, the synchronization message to the bus terminal for clock synchronization comprises: determining, by the bus controller, whether the bus controller operates in its synchronization time slice, and if so, then retrieving the synchronization message from a real-time data container of the bus container in the time slice as data to be transmitted, and transmitting the synchronization message, wherein the synchronization message carries a timestamp concerning when the synchronization message is transmitted, so that the bus terminal is synchronized in clock according to the timestamp, wherein the timestamp is derived using a clock of the bus controller. electing one of the bus controller and the bus terminal as a best master clock; determining whether an IP address of the device of the best master clock is the same as an IP address of the bus controller; if so, then determining the bus controller as a master device of clock synchronization, and transmitting by the bus controller a synchronization message to the bus terminal for clock synchronization; and otherwise, returning to the step of electing one of the bus controller and the bus terminal as the best master clock; characterized in that, the method further comprises: segmenting, by the bus controller, a transmission period of time available over a bus in the two-wire data transfer network into synchronization time slices and data time slices: the transmitting, by the bus controller, the synchronization message to the bus terminal for clock synchronization comprises: determining, by the bus controller, whether the bus controller operates in its synchronization time slice, and if so, then retrieving the synchronization message from a real-time data container of the bus container in the time slice as data to be transmitted, and transmitting the synchronization message, wherein the synchronization message carries a timestamp concerning when the synchronization message is transmitted, so that the bus terminal is synchronized in clock according to the timestamp, wherein the timestamp is derived using a clock of the bus controller.