ABSTRACT Two static equivalent methods are used to acquire equivalent parameter of power systems in this paper. These two methods combine feature and requirement of power systems and use the base-case system information and Thevenin equivalent theory for analyzing the voltage stability problem. The Q-V, P-V, P-Q curves and the minimum singular value, which has distinctive physical meaning and requires less computation work compared with the margin methods expressed by previous singular value, can be quickly got by these two methods respectively.