The invention relates to a hydraulic switching valve connected to an underground testing tubular column. The hydraulic switching valve is a hollow tube body and is provided with an outer layer, an intermediate layer and an inner layer, wherein an upper joint, an intermediate joint, a ball valve outer barrel and a lower joint are arranged on the outer layer in the axial direction; the intermediate layer is provided with a slideable hollow mandrel fixed on the intermediate joint through a mandrel shear pin; a connecting claw, a connecting pup joint, an upper seat ring and a lower seat ring are further arranged at the lower end of the mandrel; two parallel grooves are formed in the side wall of the upper seat ring, two strip-shaped motion arms are respectively embedded into the two parallel grooves, and the top ends of the motion arms are buckled with the bottom end of the connecting pup joint; a ball seat sleeve body of which the top end can be clamped and sealed by a shot ball is arranged at the upper part of the mandrel, in the inner layer; a ball valve assembly is arranged in the upper seat ring, as well as the lower seat ring, in the inner layer, and is provided with an upper ball seat, a lower ball seat and a ball valve combined into the two ball seats, a seat spring is arranged between the ball valve and the upper ball seat, and the ball valve is matched with a bulged operation end of each motion arm; an upper joint is provided with an outer circulation hole; and the mandrel is provided with an inner circulation hole and a pressure release hole positioned between the inner circulation hole and the outer circulation hole.