The invention discloses a crack soldering method. The method comprises the following steps: (1) uniformly impacting circular points at the two sides of a crack, and impacting circular points at the two ends of the crack; (2) washing the crack, beveling and grinding, wherein all of the circular points are remained on the edge of a groove; (3) performing large-area preheating from outside to inside along the crack by using a soldering gun, and starting to weld when the soldering conditions are satisfies, wherein the ends of a soldering wire circle in a melting tank all the time in a soldering process until the soldering is ended. The method disclosed by the invention can well release stress and residual stress at the two sides and the two ends of the crack and is low in working cost, good in soldering effect, convenient to operate, difficult to break down and capable of shortening the soldering time so that orderly implementation of construction can be guaranteed.