A bridge concentric direct-reading testing and adjusting instrument, comprising a cable head connected to a pressure sensor; a supporting mechanism having a pair of supporting arms; a sliding power mechanism including a power motor, a spring, an impact hammer and a one-way clutch assembly, the impact hammer slidably connected to the power motor to be rotated along with rotation of the power motor, a lower end of the impact hammer detachably connected to the one-way clutch assembly, and the one-way clutch assembly connecting the supporting arms via a transmission assembly to control opening and closing of the supporting arms; a flowmeter; and an adjusting actuator including an adjusting motor, an adjusting connector and an adjusting arm, the adjusting arm used for adjusting a waterflooding flow rate through rotation of the adjusting arm.