The invention discloses a limiting structure and an operation device for oval device welding and an application method. The limiting structure for oval device welding comprises a welding plate and a baffle, the baffle is arranged on one side of the welding plate, and the baffle is installed in a front-back adjusting manner relative to the welding plate so as to control the installed front and backsize of an oval device in a matched manner. The welding plate is provided with a pin fixed installing groove matched with an oval device pin, and a tin wire fixing structure is further arranged to form the welding operation device. Lateral welding of one or more oval devices is scientifically achieved, six-freedom-degree limitation is conducted on the oval device, the action of a tin wire is limited, and the problem of short-circuit failures caused when molten soldering tin flows to an oval device shell during welding is effectively solved; tool integration is achieved, workers can conveniently conduct operation, and the field production efficiency is obviously improved.