NOVELTY - A vanadyl sulfate electrolyte preparing method involves mixing sodium hydroxide vanadium slag and stone coal extract to prepare vanadyl sulfate solution, and adding divalent oxide, lithium borohydride and blend extracting agent. The vanadyl sulfate solution is subjected to multi-stage counter-current extraction to obtain an extract. The extract is subjected to two-phase liquid separation and washed with deionized water followed by washing with sulfuric acid solution to obtain vanadyl sulfate electrolyte precursor and subjecting the precursor to distillation to obtain a finished product.    USE - Method for preparing vanadyl sulfate electrolyte that is utilized to prepare a vanadium battery.    ADVANTAGE - The method enables preparing the vanadyl sulfate electrolyte with high efficiency in a simple and cost-effective manner.    DETAILED DESCRIPTION - A vanadyl sulfate electrolyte preparing method involves mixing sodium hydroxide vanadium slag and stone coal extract to pH of 3.0-4.0 to prepare vanadyl sulfate solution, adding divalent oxide as reducing agent and lithium borohydride with vanadyl sulfate solution and adding blend extracting agent such as P507, TBP, sulfonating kerosene to weight ratio of 20-30:10-20:40-50 for 30 minutes. The vanadyl sulfate solution is subjected to multi-stage counter-current extraction to obtain an extract. The extract is subjected to two-phase liquid separation and washed with deionized water for 5 minutes. The 100 g/l sulfuric acid solution is loaded to multi-stage counter-current reverse extraction with organic phase vanadium to obtain vanadyl sulfate reverse extracting liquid. The ammonium hydroxide, borane and extracting agent are added with vanadyl sulfate reverse extracting liquid to pH of 2 and potential value less than 100mV for 20 minutes followed by washing the organic phase vanadium with sulfuric acid solution under low conditions for 5 minutes to obtain vanadyl sulfate electrolyte precursor and subjecting the precursor to distillation to obtain 70% vanadyl sulfate electrolyte.