The invention provides a rotary vertical assembling device for thin-walled barrel-shaped components. The rotary vertical assembling device comprises a machine frame, a vertical lifting platform, a mixing and friction welding mechanism, an annular upper outward-pressing clamp and an annular lower outward-pressing clamp. The vertical lifting platform is used for lifting the thin-walled barrel-shaped components. The vertical lifting platform, the annular upper outward-pressing clamp and the annular lower outward-pressing clamp are sequentially arranged in the machine frame in a sliding manner in the vertical direction. The barrel-shaped components are clamped by the annular upper outward-pressing clamp and the annular lower outward-pressing clamp, and the annular upper outward-pressing clamp and the annular lower outward-pressing clamp rotate. The mixing and friction welding mechanism is fixed on one side of the machine frame. The assembling device adopts a vertical clamping and welding way, avoids structural distortion of the thin-walled barrel-shaped components due to self gravity, and reduces the error influence factors during the assembling process; and the clamps are uniformly distributed in the circumferential direction, flexible clamping of the thin-walled barrel-shaped components is realized, the positioning precision is ensured, the clamping and positioning errors are reduced, the automatic degree of the device is high, the stations are concentrated, the occupied area is small, the height can be controlled during the processes of feeding, clamping, welding and discharging, and the assembling efficiency is improved.