The invention discloses a direct current emergency power control method and a closed-loop power modulation module, which belong to the field of electrical engineering. The method comprises the steps that S1 whether the change amount of the current input power signal reaches a startup threshold is judged, and if the startup threshold is reached, proceeding to S2 is carried out, and otherwise S1is repeated; S2 after low-pass filtering of the change amount of the input power signal, the direct current power correction amount is acquired through a direct current power correction amount calculatingcurve; and S3 the direct current power correction amount and an output direct current power command value are superimposed to acquire a direct current power control command value. According to the invention, the closed-loop power modulation module is added to a direct current emergency power controller to increase the deceleration area of the power angle during the normal swing process and suppress the normal swing of the power angle; the acceleration area during the backswing process is reduced; the deceleration area during the backswing process is increased; the backswing of the power angleis suppressed; and the suppression effect of direct current emergency power control on the swing of the power angle is improved.