Progressive Collapse Analysis (PCA) is the base of quantitative assessment of progressive collapse-resisting capacity and progressive collapse-resisting design. There has been heightened interest among researchers of civil engineering in PCA. PCA of planar RC frame is carried on by vertical nonlinear dynamic analysis based on alternate load path method. According to responses of damage structure, progressive collapse-resisting capacity of remaining structure is evaluated. Two cases of removal of elements are analyzed, removal of columns at different stories on the same axes one by one and removal of all columns on the same axes at the same time. According to analysis of the effect of failure duration on structural progressive collapse, it is showed that the response of remaining structure is highly sensitive to failure duration of elements. The results indicate that vertical nonlinear dynamic analysis is an efficient method of progressive collapse-resisting design and progressive collapse-resisting capacity analysis.