Online stability analysis system can scan the real-time power grid, reveal the stability and risks, provide technical supports and means for scientific and predictable decision-making on grid operation,and lay a good foundation for the power grid risk prevention and fault disposal,but how to make full use of the system in practice is still a problem that many operators should focus on. The application was introduced, which of online stability analysis system in Hunan electrical power dispatch & control center,and the optimization improvement measures of the system was proposed by analysing a real example on power grid risk pre-control and accident disposal based on online stability analysis system.