To effectively suppress the larger displacement of both the isolation layer and the main structure of base-isolation structures, the top-absorption and base-isolation type seismic reduction structure (SRS) was designed, and a new non-stationary random seismic response analysis method applied to this structure was also presented. This seismic reduction structure was constructed by installing a tuned mass damper on the top of a base-isolation structure, and the hysteretic properties of both the isolation layer and each storey were simulated in Bouc-Wen and Bouc-Wen stiffness degradation model. The CCIM, which was applied to solve the non-stationary random response of SRS, was presented by introducing the composite Cotes integral into precise integral method and combining the pseudo excitation method. The dynamic reliability limits state equation, which took structural inter-storey displacement angle as the evaluation index, was established on the basis of the first excursion failure criterion. Both the high efficiency and the high precision of the CCIM were validated by computing the random seismic response of SRS and comparing CCIM's results with those of Monte Carlo method and time domain explicit Monte Carlo method, respectively. Taking the 30-storey steel frame structure as a numerical example, the random seismic response of SRS, base-isolation and non-isolation structures subjected to 8 and 9 degrees rare earthquake were computed, respectively. The analysis results indicate that the whole reliability of SRS presented is higher than those of base-isolation and non-isolation structures, and this SRS has great value in practical engineering.