The invention discloses a coolant addition method of a vanadium-containing molten iron vanadium oxidation extraction technology. The coolant addition method comprises the following steps of carrying out computation on a quality change of elements in a vanadium extraction process by vanadium oxidation extraction technology simulation according to molten iron component information, simultaneously, determining an optimum temperature zone of vanadium oxidation of the vanadium-containing molten iron vanadium oxidation extraction technology, calculating heat released by the molten iron according the quality change of the elements, drawing and analyzing a heat release enthalpy change curve according to heat release conditions, and determining coolant addition starting time and coolant addition stopping time according to the heat release enthalpy change curve. The coolant addition method can determine reasonable coolant supply parameters, realizes good control of a molten pool temperature in the optimum temperature zone of vanadium oxidation, improves vanadium extraction efficiency, improves vanadium slag quality, reduces a production cost and has an important guidance meaning for fine production. The coolant addition method improves coolant utilization efficiency and reduces a coolant use amount.