The invention relates to the technical field of thick oil recovery, in particular to a removable electric ignition device for in-situ combustion and an application method thereof. The bracket of the device is positioned at a main gas injection well section, the upper part of the bracket is an inclined opening, the lower part of the bracket is a trumpet-shaped downward opening, the inner diameter at the upper part of the bracket is smaller than the outer diameter of an igniter, an underground blowout preventer valve is positioned at the position about 2-3 oil pipes under a wellhead, the upper part and the lower part of the underground blowout preventer valve are both connected with the screw threads of the oil pipe, the underground blowout preventer valve is connected with a hydraulic control pipeline, a wire connector, a connecting sieve pipe and the igniter are made into a whole from top to bottom, the lower end of the igniter is made into a conical opening which has the same angle of the inclined opening of the bracket, the conical opening at the lower end of the igniter is positioned on the inclined opening of the bracket to form conical platform contact, and a intermediate frequency power supply control cabinet, a cable conductor I, a cable conductor II and the wire connector are connected in sequence. According to the invention, the reuse of a mineshaft is realized, the mineshaft can be safely and successfully tripped out, and the defect that in the traditional electric ignition system, the blowout situation is easy to cause when a heater is being tripped out with pressure is overcome.