The invention discloses a method for examining loosing of iron tower bolts. The method combines the iron tower vision measurement technology with theoretical calculation to predict loosing of bolts, and adopts the vision measurement method to measure vibration of iron towers. By adopting the non-contact method, potential safety hazard caused by iron tower climbing measurement is avoided, natural wind is utilized as the power source, and the method is time-saving and labor-saving as compared with artificial iron tower climbing cable-lanyard measurement.