According to the characteristics of energy distribution and economic development in China，the AC-DC hybrid power grid is an inevitable trend of the future power grid construction.However，combined running of a large-scale AC-DC power grid will bring potential risks to the security and stability of the power system.Based on this，the AC-DC match planning method is discussed from the angle of constructing timing optimization.The short circuit ratio is taken as an indicator and a method of measuring the rationality of large-scale AC-DC matching and the indicator is introduced into the objective function in the form of security and stability cost after its obfuscation.Meanwhile，in view of various construction and operation constraints of the hybrid grid，an AC-DC timing optimization model is developed by considering stability and economy at once. A New England10-machine39-node power system is used as the test system，the results showing that the proposed model is able to cope with the timing of the AC and DC line construction effectively on the premise that the security and stability of the grid will be ensured.