The invention provides an ultrahigh voltage direct current transmission valve cooling rotating equipment fault diagnosis method. The method comprises the steps of sound collection, digital filtering, frequency feature extraction, break variable detection and the like. The method can be used for online diagnosis and offline diagnosis. The method is characterized in that under the continuous diagnosis mode, if it is determined that abnormality exists, a sound sample at the moment is exported to a designated directory, a technician is allowed to adopt the offline diagnosis mode for further analyzing the exported sound sample; when rotating equipment is operated, if a machine fault appears, a sound signal will change suddenly, the fault moment of the rotating equipment can be found in time when some break variable points are detected, an overhaul professional person can enter the position in time, the equipment is prevented from continuing to be deteriorated, the reliability of a valve cooling system is directly improved, and the good practical and popularized value is achieved.