The invention relates to an automatic control method in calcium-carbide-method PVC production, especially to an automatic control method for a generator feeding speed in calcium-carbide-method PVC production. The control method based on three-element uniform control is characterized in that a generator feeding speed regulator is used for realizing balancing of three parameters including a generator pressure, a generator temperature, and a generator acetylene cabinet height by DCS configuration. On the basis of regulation of a set value of the generator feeding speed regulator, generator load adjustment is carried out and a uniform load state of all generators is realized, and a given high limit range of each generator is determined; according to a water adding valve temperature control situation and a pressure situation of each generator, an output upper limit of the feeding speed regulator is set, and the pressure and temperature of the generator as well as a height upper limit alarming value of the generator acetylene cabinet are set. Compared with the prior art, the provided method has the following beneficial effects: the regulator set value of the generator feeding speed regulator can be adjusted timely; the production load is balanced; the production is stabilized; the labor intensity is reduced; the automation level of production is improved; and the production security is guaranteed.