Abstract: A method for calculating the ductility reduction factor of a multi-degree-of-freedom system was proposed based on the capacity spectrum theory. The ductility reduction factors, overstrength factors, and strength reduction factors of 9 RC frames according to current Chinese seismic code with different heights and design seismic zones were calculated using the Pushover method. It is found that the structures with a higher design seismic level have a lower reserve strength when they have the same height, while the reserve strength will decrease with increasing height at the same design seismic level. The current Chinese seismic code was evaluated and some advices were proposed for its future modification.