This paper presents a LTCC multi-channel flip-chip interconnect structure which modeled and simulated by HFSS simulation software, and focusing on the microwave transmission characteristics of flip-chip interconnect structure. In this paper, by using factorial analysis, the most significant parameters which can affect the microwave signal transmission performance of flip-chip interconnect structure are found to be: the overlap length between the transmission line, coplanar waveguide transmission line width and flip-chip bump diameter. The simulation model was processed and measured, form 1GHz to 35GHz, the tested insertion losses of the 4-channel back to back flip-chip interconnect structure are both batter than −0.9dB, and the return losses are lower than −15.2dB, the phase of each channel maintains a linear consistent. The above results show that the flip-chip structure have good millimeter wave transmission characteristics, and can be applied to the interconnection between the multi-channel subsystems.