Expansion rotating tool for branching well

Disclosed is a telescopic rotatable tool for a multilateral well. The telescopic rotatable tool of the multilateral well comprises an upper joint (1) and a lower joint (6), the upper end of the upper joint (1) is an internal thread, the inner wall at the lower end of the upper joint (1) has an inner boss (5), the lower end of the lower joint (6) is provided with an external thread, and the outer wall at the upper end of the lower joint (6) has an outer boss (2), a baffle ring (4) is arranged in an annular groove of the lower joint (6), the lower joint (6) is positioned in the upper joint (1) and the outer boss (2) is clamped with the inner boss (5), and an O-shaped sealing ring (3) is disposed between the lower joint (6) and the upper joint (1). The tool can greatly reduce the labor intensity and simplify procedures.