Abstract: With the export of domestic units to the “Belt and Road” countries, the excitation system modeling and PSS（power system stabilizer）test are carried out in overseas projects, and the relevant requirements for different simulation software modeling are put forward.It conducts an excitation system modeling test for an overseas 300 MW unit based on ETAP software, and compares it with the no-load test to verify the correctness of the model.PSS parameter setting is mainly completed using Matlab to calculate the un-compensation characteristics of the excitation system, conducts PSS parameter setting, confirms the critical gain of the PSS using the root locus method, and finally completes the ETAP excitation system model and PSS parameter calculation.