Based on the in-depth study on the characters of power supply system such as power flow distribution

generator output and cost curve and seismic security analysis and control

the Security Constrained Optimization Algorithm（SCOA） is employed to study seismic security control of power supply system. The linear model of power grid

constrained conditions of generators output and transmission lines and objective function about this method are discussed profoundly in this paper

and the implementation process is got.Finally

program compiled by Fortran language and Matlab is made up which involves analysis of power grid load flow

sensitivity analysis of security and SCOA.The program can provide control measures and dispatch cost in time.The practicability and superiority of this method are verified by an example. This research can be a basis for the study of load flow control

functional recovery and economic analysis of power supply system.It can also assure the best performance of the system after damage and has great practical significance.