The embodiment of the invention provides a water 
nozzle for a water 
injection well in an 
oil field. The water 
nozzle for the water 
injection well in the 
oil field comprises an opening determination device, an opening adjustment device, a 
piston rod and a valve, wherein the opening determination device is used for automatically collecting the current formation 
pressure data according to a preset period, and determining the current opening, corresponding to the formation 
pressure data, of the valve; the opening adjustment device is connected with the opening determination device and the 
piston rod, and is used for pushing the 
piston rod to move forwards or backwards according to the determined current opening; the valve is fixed on the 
piston rod, and is used for moving forwards or backwards along with the 
piston rod, so as to reach the determined current opening. With the adoption of the scheme, the formation pressure can be automatically collected according to the period, and the opening of the valve can be adjusted according to the formation pressure, so that the water injection effect is improved, the injected 
water volume of the stratum where a blanking plug is positioned is guaranteed, and the amount of labor of manual measurement and adjustment is reduced.