The invention relates to a transformer coil and solid insulating material drying method including the following steps of (1) heating is carried out in a drying chamber; (2) placing a secondary coil, a primary coil, an iron core and a cushion block into a transformer oil tank; (3) installing a gas relay valve, a gas relay, an oil conservator, an oil conservator support, a respirator connection pipe, a respirator, a radiator and radiator valves, injecting transformer oil after sealing and vacuumizing, and staying still for 24 hours; (4) opening the gas relay valve, closing the upper radiator valve and the lower radiator valve and applying voltage to the primary coil, wherein 10% of rated voltage is applied to the primary coil of the transformer for 24 hours firstly, gas in the gas relay is exhausted and 20% of the rated voltage, 30% of the rated voltage, 40% of the rated voltage, 50% of the rated voltage, 60% of the rated voltage, 70% of the rated voltage, 80% of the rated voltage, 90% of the rated voltage and 100% of the rated voltage are sequentially applied according to the procedures. By means of the means, a coil and insulating oil can be dried, the water content in a solid insulating material can be further lowered, and discharge of water in solid insulation is facilitated.