Based on a 8-story reinforced concrete plane frame structure, The FOSM method, the tornado diagram method and the mathematical statistics method were used to discuss the sensitivity of the top displacement to uncertainties such as the seismic intensity, the site characterization, the lateral load loading mode, the structural weight, the strength and elastic modulus of concrete and the strength and elastic modulus of the rebar. The results show that the sensitivity of the top displacement to the demand curve is much stronger than the capacity curve. Accordingly, considering the uncertainty of the demand curve and ignoring the uncertainty of capacity curve when studying the pushover analysis method based on the probability theory can not only greatly simplify the analysis procedure but also ensure the accuracy of the results.