The invention discloses a method for relieving pressure pulsation hazards caused by cavitation of a tubular water turbine. The method is characterized by comprising the following steps of 1), enablingguide vane number Zg and rotating wheel vane number Zr in a non-integer multiple relation when the guide vane number Zg and rotating wheel blades number Zr of the tubular water turbine are selected;2), optimizing design of a rotating wheel chamber and a tail water pipe connected with the rotating wheel chamber into a whole; and 3), optimizing design of components of a high-pressure side unit ofa rotating wheel and the structure of a factory building. According to the method, through the composition selection of the rotating wheel blades number and the guide vanes number, anti-resonance design of the rotating wheel chamber and structural parts at the rotating wheel high-pressure side, strong vibration and resonance hazards caused by gap cavitation of the tubular water turbine are effectively reduced.