The invention relates to an automatic water break protection device. The automatic water break protection device is characterized in that a lever rotationally mounted on a mounting seat is connected with a support bar arranged in a pressure water bucket and a valve rod of a two-way valve; when the water pressure in the pressure water bucket is larger than 0.15 MPa, a pressure plate slides upwards along the inner wall of the pressure water bucket to drive the support bar to move upwards, the support bar pushes the lever to rotate, the end, connected with the support bar, of the lever ascends, while the end, connected with the valve rod, of the lever descends, the valve rod of the two-way valve is pushed to face downwards, the two-way valve works, and a gas inlet and a gas outlet of the two-way valve are communicated to realize gas supply; and when the water pressure is smaller than 0.07 MPa or after a water ball valve is closed, the two-way valve returns to the original position, and the gas inlet and the gas outlet are disconnected to realize gas break so as to achieve an automatic water break protection function. The automatic water break protection device is quick in gas supply and break, has a good water break protection effect and avoids potential safety hazards.