As the Ｒayleigh damping coefficient remarkably influences the time-history analysis accuracy of the seis-mic response of quay crane structures，an improved calculation method of Ｒayleigh damping coefficient is proposed．In this method，both the spectrum characteristics of the ground motion and the frequency characteristics of the structure itself are taken into consideration，which makes the calculation more reasonable． Then，a series of dynam-ic time-history analyses of quay crane structures are performed by using different calculation methods of damping co-efficient，and the results are compared with those obtained by the shaking table test． It is found that，under differ-ent seismic wave excitations，when the numerical calculation results are closest to the test ones，different damping coefficient calculation methods are adopted; and that the time-history calculation results of quay crane structures ob-tained by the improved method under various seismic response accord well with the experimental ones．