Aiming at the current situation of realtime data stream transmission of different data bandwidths and fixed transmission speed of FPGA highspeed transceivers, this paper proposes a broadband adaptive serial data realtime transmission system. The sender first performs bitwidth conversion and crossclock domain processing on the transmitted data, then marks and encodes the data, and finally transmits data through the GTX transmission port. The receiving end first parses the valid data according to the control code and the flag bit, and finally performs bit width conversion and cross clock domain processing through the receiving buffer module. The system is applied to the acquisition data transmission of the oscilloscope. When the GTX line speed is 45 Gbps, the data of the 15 types of acquisition cards can be correctly received. The transmission system only needs to modify the write data bit width of the buffer FIFO at the transmitting end for different acquisition cards, which has the characteristics of strong code portability and strong hardware platform compatibility.