A data transmission method performed by a photoelectric conversion device, comprising: extracting data to be transmitted from a received Common Public Radio Interface, CPRI, frame; inserting the data to be transmitted into an Ethernet frame, a period of the Ethernet frame being the same as a period of the CPRI frame; and sending the Ethernet frame; characterized in that in a manner of setting packet sequence number control words for Ethernet frames, an Ethernet interface receiving the Ethernet frame inserted with the data to be transmitted parses the packet sequence number control words for the Ethernet frames to analyze a frame header position of the Ethernet frame, thereby implementing synchronous transmission of the CPRI frame data and the Ethernet frame data; wherein inserting the data to be transmitted into the Ethernet frame comprises: determining a data volume borne in each Ethernet frame according to a data transmission rate of an interface transmitting the Ethernet frame; judging whether the data volume borne in each Ethernet frame is smaller than a data volume of the data to be transmitted or not; under the condition of judging that the data volume borne in each Ethernet frame is smaller than the data volume of the data to be transmitted, inserting the data to be transmitted into multiple Ethernet frames, or screening data in a preset data volume from the data to be transmitted, inserting the data in the preset data volume into an Ethernet frame and discarding the other data, except the screened data in the preset data volume, in the data to be transmitted. extracting data to be transmitted from a received Common Public Radio Interface, CPRI, frame; inserting the data to be transmitted into an Ethernet frame, a period of the Ethernet frame being the same as a period of the CPRI frame; and sending the Ethernet frame; characterized in that in a manner of setting packet sequence number control words for Ethernet frames, an Ethernet interface receiving the Ethernet frame inserted with the data to be transmitted parses the packet sequence number control words for the Ethernet frames to analyze a frame header position of the Ethernet frame, thereby implementing synchronous transmission of the CPRI frame data and the Ethernet frame data; wherein inserting the data to be transmitted into the Ethernet frame comprises: determining a data volume borne in each Ethernet frame according to a data transmission rate of an interface transmitting the Ethernet frame; judging whether the data volume borne in each Ethernet frame is smaller than a data volume of the data to be transmitted or not; under the condition of judging that the data volume borne in each Ethernet frame is smaller than the data volume of the data to be transmitted, inserting the data to be transmitted into multiple Ethernet frames, or screening data in a preset data volume from the data to be transmitted, inserting the data in the preset data volume into an Ethernet frame and discarding the other data, except the screened data in the preset data volume, in the data to be transmitted. determining a data volume borne in each Ethernet frame according to a data transmission rate of an interface transmitting the Ethernet frame; judging whether the data volume borne in each Ethernet frame is smaller than a data volume of the data to be transmitted or not; under the condition of judging that the data volume borne in each Ethernet frame is smaller than the data volume of the data to be transmitted, inserting the data to be transmitted into multiple Ethernet frames, or screening data in a preset data volume from the data to be transmitted, inserting the data in the preset data volume into an Ethernet frame and discarding the other data, except the screened data in the preset data volume, in the data to be transmitted.