Abstract: A gradient structure high-speed circuit differential line with corner segmented impedance control is constructed and the differential signal is modeled and analyzed by HFSS three-dimensional electromagnetic simulation software. Through the simula-tion analysis of mixed-mode S parameters, the results show that compared with the differential signal design method of parallel structure, in the range of 10 GHz, differential mode to differential mode of the proposed gradient structure differential signal increases 58. 7%, and the differential mode to common mode decreases 38. 3%. The test shows that the Sd2d1 parameters and Sc2d1 simula-tion results of the differential line with GND hole gradient structure are in good agreement with the measured results, differential mode to common mode of the differential circuit is effectively suppressed, and differential signal transmission efficiency is improved. The electric field distribution shows that the gradient structure design method greatly improves the electric field distribution at the corner of the differential circuit, avoids the electric field aggregation between the transmission lines of the differential circuit, reduces the common mode noise and reflection loss of the differential signal, and realizes the continuity of high-speed differential signal transmission.