Abstract: As vehicle-to-everything （V2X） communications evolve toward 6G to empower intelligent transportation systems， an in-depth understanding of the cross-band channel characteristics in complex environments is paramount for robust system design. Existing research inadequately characterizes multiband channel features in complex terrains， and the current 3GPP Rural Macro standard model struggles to capture the severe fading induced by undulating topography and vegetation shadowing accurately. To address this issue， focusing on a typical hilly scenario， this study conducts comparative channel measurement and modeling across three key frequency bands： 1.8 GHz， 3.3 GHz， and 5.9 GHz. By constructing a comprehensive statistical channel model that encompasses large-scale fading， small-scale fading， and cluster characteristics， significant discrepancies are revealed in the fading behaviors and clustering properties among different frequency bands in hilly environments. The research findings uncover a pronounced frequency dependence of radio propagation in such scenarios： higher frequency bands suffer from more severe path loss and multipath fading， whereas lower frequency bands exhibit severe signal time dispersion. Furthermore， the dynamic evolution of multipath clusters demonstrates that the cluster survival lifetime is highly dependent on the carrier frequency， whereas the microstructure within clusters is primarily driven by the environmental geometric topology. The established model effectively corrects the prediction deviations of the existing 3GPP standard model in hilly scenarios. The findings provide a solid foundation for V2X channel modeling in hilly terrains and offer critical insights for the design of future 6G-V2X systems.