The utility model relates to a hydraulic vibrator for drilling. The hydraulic vibrator comprises a hydraulic driving assembly, a fixed valve assembly, a bottom assembly and a vibratory short joint, wherein the vibratory short joint is connected with the hydraulic driving assembly; a rotor is connected with a vibratory valve; the fixed valve assembly is arranged on the bottom assembly; and a dynamic shell is connected with the bottom assembly. The drilling fluid drives the rotor to rotate, and the rotor drives the vibratory valve to vibrate, so that through holes of the vibratory valve and the fixed valve are mutually staggered to form simple-harmonic pressure waves; the pressure waves are upwards transferred to a disc-shaped spring, and a vibratory shell is driven to do continuous and simple-harmonic vibration in the axial direction, so that the friction resistance between a drilling column and the well wall is effectively improved, and the drilling speed is increased; and simultaneously, the pressure wave is downwards transferred to jet flow of a drilling bit, the periodical change of rock-breaking pressure is enhanced, and the rock is effectively broken. The hydraulic vibrator has the characteristics of simple structure, convenience in operation, safety, reliability, low pressure reduction, strong adaptability and no influence on a drill structure and the like, and has the important significance for increasing the drilling speed and reducing the cost.