The invention discloses a temporary bracing device of a tilting pylon leg of a cable-stayed bridge. The temporary bracing device is characterized in that two corresponding steel plates with threaded holes are correspondingly pre-embedded in concrete of a first tilting pylon leg and a second tilting pylon leg of a cable-stayed bridge pylon column, and first bolts and second bolts are correspondingly mounted in the threaded holes of the pre-embedded steel plates; first bracing heads, first bracing steel pipes, second bracing steel pipes, third bracing steel pipes, first jacks, second jacks, jackseats, first wedges, second wedges and second bracing heads are assembled together, and thus first temporary bracing devices of the tilting pylon leg of the cable-stayed bridge are composed; and nutsare correspondingly mounted on the first bolts and the second bolts, and the first temporary bracing devices of the tilting pylon legs of the cable-stayed bridge is mounted and fixed to the inner side walls of the first tilting pylon leg and the second tilting pylon leg.