The invention discloses an under-pressure welding method and belongs to the field of equipment leakage treatment. The method includes the steps that whether the thickness of the edge of a leakage point is larger than three mm or not is judged; when the thickness of the edge of the leakage point is larger than three mm, the type of the leakage point is determined according to the shape, size and position of the leakage point, and the types of the leakage point include small holes, cracks, regular holes of a regular part of equipment, irregular holes of the regular part of the equipment and holes of an irregular part of the equipment; and the leakage point is welded and repaired according to the type of the leakage point. According to different types of the leakage point, the leakage point is treated respectively through under-pressure welding modes including direct welding, welding after leaking stoppage through a plugging device, flow guide welding through a flow guide pipe and the like, and the pertinence, operability, generalizability and reliability are quite high.