The invention belongs to the technical field of voltage and reactive control for an electric system and particularly relates to a method for controlling voltage reactive variables of a high-voltage power grid transformer substation. The method comprises the following steps of: A, determining an application condition of a transformer element; B, establishing a mathematical model for the transformer element; C, taking a mathematical expression reduction result from the mathematical model; D, determining the voltage reactive variables of the transformer substation and calculating the relationship among the reactive variables; E, determining a control range of the voltage reactive variables of the transformer substation; and F, providing a control strategy for the voltage reactive variables of the transformer substation. The control method disclosed by the invention has the advantages of strong operability, complete consideration and rational scheme and has high practical value and good market prospect.