The stochastic dynamic behavior of power secondary system is opaque and difficult to visualize, which obviously hinders to control the uncertainties brought by the strong dependence on information and communication technologies in new power systems. In this paper, the steady-state analysis method, static security analysis method, and transient analysis method for power secondary systems are first proposed. The smart substation secondary system with complex functional descriptions is taken as the research object. Through simulation technology development, a smart substation secondary system simulation tool integrated into general network simulation software has been created, which fidelity depicts the entire process of digital information transmission, flowing, and processing in the secondary system. By combining the proposed simulation tester at the device level, path tracking and delay recording technology at the system level, action characteristic display technology and simulation acceleration technology at the scenario level, and taking the actual engineering project as an example, the steady-state analysis, static security analysis, and transient analysis of the power secondary system under network transmission steady-state scenarios, secondary component (partial) failure scenarios, and circuit breaker failure scenarios have been achieved.