NOVELTY - A vanadium sulfate electrolyte preparing method involves taking calcium hydroxide and vanadium slag, adding vanadyl sulfate solution to obtain extract of vanadyl sulfate solution, and extracting P507: TBP: sulfonating kerosene in vanadyl sulfate solution. The extract is separated, washed and loaded with vanadium organic phase and extracted to obtain two separate extracts followed by extracting, washing, loading with vanadium organic phase, placing in reverse extraction to obtain a vanadyl sulfate electrolyte precursor and distilling the obtained precursor to obtain the finished product.    USE - Method for preparing a vanadium sulfate electrolyte used in a vanadium battery.    ADVANTAGE - The method enables preparing the vanadium sulfate electrolyte in a simple and cost-effective manner.    DETAILED DESCRIPTION - A vanadium sulfate electrolyte preparing method involves taking calcium hydroxide and vanadium slag from stone coal extraction, adding vanadyl sulfate solution to obtain extract and maintaining pH of 3.0-4.0, taking 5 times of sodium thiosulfate pentahydrate according to divalent oxide reducing agent to obtain extract of vanadyl sulfate solution, extracting P507: TBP: sulfonating kerosene in vanadyl sulfate solution for 30 minutes and placing in multi-stage counter-current extraction for 10 minutes to obtain the extract. The extract is separated and washed with deionized water, loaded with load vanadium organic phase, washed using 100 g/l sulfuric acid solution for 5 minutes and placed in multi-stage counter-current reverse extraction to obtain two separate reverse extracts followed by adding ammonium hydroxide, titanyl sulfate to the obtained reverse extract, adding ascorbic acid to adjust the solution potential value to less than 100 mV, comparing the extract in o/A=5-1:1, extracting for 20 minutes, washing the separated reverse extract with 50 g/l sulfuric acid, loading 3 g/l vanadium organic phase by comparing with 0/A=3:1 and placing in multi-stage counter-current reverse extraction to obtain a vanadyl sulfate electrolyte precursor and distilling the obtained vanadyl sulfate electrolyte precursor to 70% to obtain the finished product, where the weight ratio of P507: TBP: sulfonating kerosene is 20-30:10-20:40-50.