Abstract: The dynamic reliability evaluation of urban building cluster is of great significance for regional disaster prevention and mitigation. The spatial variability of ground motion and the soil-structure interaction caused by site effect have important impacts on nonlinear seismic response of building cluster. Yet existing regional earthquake disaster simulation methods based on deterministic analysis cannot reasonably reflect the overall behavior of the stochastic dynamic system of building cluster. The measured earthquake field excitations and the soil-structure interaction effect are introduced, and the time-domain solution method of the building cluster system considering the structural nonlinearity is developed in it. Further, based on the idea of probability conservation, the framework of dynamic reliability evaluation of stochastic building cluster based on the probability density evolution method is established. Taking a building cluster of high-rise frame structures as an example, the deterministic nonlinear seismic response analysis considering site effect is carried out. Next, the dynamic reliability evaluation of a stochastic building cluster is completed, and the impact of site effect on dynamic reliability of building cluster is evaluated. Finally, some useful conclusions are obtained.