The invention provides an on-site drying method for a disintegrating transportation type ultra-high-voltage alternating-current transformer. The on-site drying method comprises the steps that s1, movable kerosene gas-phase drying equipment is transported to a site of the disintegrating transportation type ultra-high-voltage transformer; s2, a thermocouple is mounted in an oil tank of the disintegrating transportation type ultra-high-voltage alternating-current transformer and used for monitoring the temperature in the oil tank; s3, a heat preservation device is arranged outside the oil tank ofthe disintegrating transportation type ultra-high-voltage alternating-current transformer; s4, a jacking device is arranged on the lower portion of the disintegrating transportation type ultra-high-voltage alternating-current transformer; s5, the movable kerosene gas-phase drying equipment is connected with an oil tank connector of the disintegrating transportation type ultra-high-voltage alternating-current transformer through a pipeline; and s6, the movable kerosene gas-phase drying equipment is operated to dry the oil tank of the disintegrating transportation type ultra-high-voltage alternating-current transformer. Compared with the prior art, the on-site drying method for the disintegrating transportation type ultra-high-voltage alternating-current transformer has the advantages of short drying period, high drying efficiency, thorough drying and the like.