In the process of designing Flip Chip packaged chips,there are issues such as discontinuities in transmission line impedance and excessive crosstalk.In the paper,a simulation analysis and design method based on impedance and crosstalk is proposed from two aspects of stack setting and plate medium thickness,which mainly involves two aspects:for the impedance mutation problem caused by the signal plane of reference being divided,the signal has a complete return path by adding a plane of reference,so that the impedance of the transmission line at the plane division is reduced from 167.5 Ω to 52.5 Ω.For the problem of high crosstalk coefficient between lines caused by excessive wiring density,the maximum crosstalk coefficient between transmission lines is reduced from 17.26% to 14.01% by reducing the dielectric thickness of the plate.The analysis and simulation results show that the method effectively reduces the potential signal integrity risk in chip design,and improves the reliability and stability of the chip.