Abstract: Based on a double-deck viaduct, two double-deck viaduct piers with different column longitudinal reinforcement ratios are designed and the influence of the longitudinal reinforcement ratio on the seismic performance of double-deck viaducts is investigated with pseudo-static test and numerical analysis. The experiment results show that the beam and lower-level beam-column joints of the high reinforced pier suffer severe damage. When the reinforcement ratio is reduced, damage mainly appears on the column, and the level of damage on the beam and the joint is mitigated effectively. Based on the experiment results, a finite element model of the pier is built and used for parametric analysis. The analysis results indicate that when the column longitudinal reinforcement ratio increases, the ductility capacity of double-deck viaducts decreases and the beam would collapse before the column, which disobeys the performance objective of strong beam and weak column.