The invention discloses a data transmission method and a data transmission device, relates to the technical field of information, and being capable of reducing complexity of network operation and maintenance. The method is applied to a data transmission framework comprising sending end equipment respectively corresponding to each business in a metropolitan area network, a hierarchical enhanced optical transport network (PE-OTN) and receiving end equipment respectively corresponding to each business, wherein the PE-OTN comprises at least one piece of PE-OTN equipment, access layer equipment corresponding to the single business performs data interaction with the receiving end equipment via the PE-OTN equipment; the business sending end equipment firstly acquires data information corresponding to the business, the business sending end is business access layer equipment, then data information corresponding to the business is sent to the receiving end equipment via the PE-OTN equipment corresponding to the business, and the data receiving end is business core network equipment or business access layer equipment. The method and the device provided by the invention are applicable to data transmission of each business via the PE-OTN equipment.