The invention discloses a screw axial force construction method for a cable clamp of a suspension bridge and relates to the field of bridge engineering construction. The screw axial force construction method comprises the steps that the spreading time t0 of ultrasound in to-be-mounted screws under the non-stress state in the axial direction is measured, and a spanner is used manually to screw the screws and nuts; jacks are used for tensioning the screws to 60% of designed construction axial force Fn, the spanner is used manually to screw the nuts, and the jacks are dismounted; the spreading time t1 of the ultrasound inside the screws under the current stress state in the axial direction is measured, the current temperatures T of the screws are measured, and the current axial force F1 of the screws is calculated according to a formula, specifically, the rotating angle theta of the nuts relative to the screws when the axial force of the screws is between the current axial force F1 and the designed construction axial force Fn is calculated according to a formula; and the jacks are used for tensioning the screws to 110% of the design construction axial force Fn, the nuts are screwed by the angle theta in the screwing direction, and the jacks are dismounted. The screw axial force of the cable clamp can well meet the design construction requirement, axial force inspection after construction is facilitated, the cable clamp is prevented from sliding after being mounted, and the safety of a bridge in use is improved.