In addition to the type of input signal, phase compensation method of power system stabilizer (PSS) is also very important for SSO. Four types of PSS are designed. These PSSs are speed-based PSS with a first-order lead compensation block, speed-based PSS with a second-order lead compensation block, speed-based PSS with a third-order lag compensation and then inverting, and power-based PSS with a lag compensation block. The frequency characteristics of PSS and electrical damping characteristics with or without PSS are analyzed. The impact of phase compensation methods of PSS on subsynchronous signal is also studied. The results show that the speed-based PSS with lag compensation and inverting almost has no effect on SSO. This kind of PSS can use the ideal speed deviation as the input signal, and avoid the torsional sensitivity. It can also suppress the low frequency oscillation effectively. This kind of PSS is feasible.