The invention discloses a construction method for enabling a subway shield section to penetrate through an existing station. According to the method, there is no condition for the construction of pilecutting vertical shafts on both sides of the enclosure structure of the existing station, and there is no condition for setting up a shield maintenance well in a newly-built subway tunnel; a construction vertical shaft is constructed by utilizing a finite space at periphery of the existing station and downwards excavated to the elevation position of the shield tunnel, and then the enclosure structure of the existing station is broken through applying the construction cross channel and the pile cutting channel; and the shield tunnel is temporarily supported by adopting the form of fiberglass ribs and steel bar combination grille support through the section pile cutting channel, and after the breaking of the existing envelope structure is completed, and C15 concrete is used for channel backfilling. According to the method, the difficult problem that the shield penetrates downward through the existing envelope structure, and safety and stability of existing station structures in the construction process are guaranteed; and the damage of a cutter head caused by directly acting on the enclosure structure by the shield can be avoided, the construction risk is effectively controlled, andsafe and normal operation of subway existing lines is guaranteed.