The invention discloses an online emergency control decision-making method considering transient state and static state security and stability constraint, and belongs to the security and stability emergency control technical field of the electric power system. For overcoming the problems that multiple kinds of problems exiting in the security and stability of the large power grid are mingled, and the online decision-making time is short, different types of control measures are chosen specific to different kinds of problems exiting in security and stability; the control measures of each type are screened based on the control performance indexes separately; the screened measures of different controllable equipment are enumerated and combined; the enumerated and combined measures are screened through the power sensitivity based overload security verification and power frequency characteristic based transient state frequency security verification; and finally, the screened enumerated and combined measures are subjected to transient state and static state security and stability quantitative evaluation by adopting a cluster computing mode. The calculation strategies are classified and sequenced specific to the problems exiting in security and stability, so that the rapid and optimized decision making of the online emergency control considering the transient state and static state security and stability constraint is realized.