The invention provides an upsetting self-locking type steel claw hydraulic clamp for friction welding, wherein a rotating clamp body (3) is positioned via a stop opening and connected to the main shaft of a main shaft box, and can rotate along with the main shaft. The upsetting self-locking type steel claw hydraulic clamp for friction welding is characterized in that an upper clamping block (1) and a lower clamping block (11) are installed on the rotating clamp body (3), the upper clamping block (1) and the lower clamping block (11) are respectively connected to the rotating clamp body (3) via an upper rotating shaft (2) and a lower rotating shaft (10), and capable of respectively rotating around the upper rotating shaft (2) and the lower rotating shaft (10), and the two ends of an oil cylinder (8) are respectively connected to the upper clamping block (1) and the lower clamp block (11); the upper clamping block (1) and the lower clamp block (11) are respectively provided with gear teeth meshed with each other, and the upper clamp block (1) is provided with two V-shaped grooves.