Abstract: The data acquisition system is the core component of Digital Storage Oscilloscopes (DSO). With the gradual increase in the bandwidth and sampling rate of oscilloscopes, the single-chip Analog to Digital Converter (ADC) + Field Programmable Gate Array (FPGA) architecture is difficult to meet ultra-high-speed and multi-channel application scenarios. Therefore, data acquisition systems in high-end oscilloscopes generally adopt a 'Master-Slave' FPGA control architecture. Under this architecture, the synchronous transmission of signals between multiple FPGAs is an important prerequisite for achieving synchronization and accurate acquisition of the acquisition system. This paper proposes a method for high-speed signal synchronous transmission between FPGAs to solve the problem of signal synchronization transmission between multiple FPGA boards. With help of FPGA's IODELAY unit, the most stable synchronization transmission interval is found through test data training, and synchronization transmission between multiple FPGAs is realized. Experiments on a domestic digital oscilloscope shows that this method can effectively achieve synchronous transmission of high-speed signals between FPGAs.