A device for controlling welding stress deformation by welding with point-to-point extrusion relates to a device for controlling welding stress deformation, and aims at the problems that in the existing welding technology, when sheets made from materials such as aluminum and titanium alloy are welded, new stress concentration is easily formed, the equipment is huge, the manufacturing cost is high, the working noise is big and the effect of controlling stress deformation is poor. A reducing motor is connected with a transmission shaft through a coupling; the transmission shaft is supported by two bearing seats and fixedly provided with an eccentric wheel thereon; a flange plate is fixedly arranged on a push rod housing and connected with a bottom plate fixedly; the upper end of the push rod housing is arranged in a through hole on the bottom plate; a compression spring is arranged between a boss at the upper end of the push rod housing and the bottom plate; the upper end face of a push rod is in contact with the edge end face of the eccentric wheel; one end of a guide post is fixedly connected with the push rod and the other end thereof passes through a slotted hole on the push rod; and the upper end of an extrusion head is fixedly arranged on the push rod and a groove is processed on the lower end face of the extrusion head. The device is simple in structure, low in cost and small in working noise, has favorable effect of controlling the stress deformation, and can improve the distribution state of residual stress.