The invention provides a method for manufacturing liquid tantalum electrolytic capacitors, and electrolyte preparation thereof. On the basis of the prior production process, additives are added to working electrolyte in a process of manufacturing liquid tantalum electrolytic capacitors so as to reduce hydrogen atoms or hydrogen molecules produced by H+ on the inner wall of a silver shell and increase the thickness of electric double layers. The electrolyte is shake-soluble working electrolyte, and consists of high-purity silica sol aqueous solution, concentrated sulfuric acid, sulfate, and hydrated chloroplatinic acid. A preparation method for the electrolyte comprises: taking 28 to 35 portions of silica sol, 9 to 12 portions of concentrated sulfuric acid, platinum aqueous solution accounting for 0.1 to 2 percent of the total weight of the electrolyte and 0.1 to 1.5 percent of sulfate according to volume ratio; preparing platinum acid into 8 to 10 percent aqueous solution; adding the platinum acid and the sulfate to the silica sol pro rata and mixing the three well; and adding corresponding proportion of concentrated sulfuric acid, mixing well and obtaining the working electrolyte.