The conventional multi-support response spectrum methods can only compute the mean of struc-tural peak response

but fail to compute its variance

thus it is impossible to apply them to the seismic reli-ability analysis of structures. In this paper

a simplified response spectrum method for random vibrationanalysis of structures subject to multi-support excitations is first introduced

Then

a seismic reliabilityanalysis procedure

based on multi-support response spectrum method

is proposed which is validatedthrough an example structure of a two-span continuous beam by Monte Carlo simulation. It can be con-cluded that the response spectrum method is of high precision.