The invention relates to a sports beverage and a preparation method thereof and belongs to the technical field of production of functional foods. The sports beverage is composed of sweet materials, taurine, isoleucine, valine, L-carnitine, leucine, sodium chloride, potassium chloride, calcium lactate, magnesium sulfate, edible essence and pure water. Particularly, the preparation method comprises the following steps: adding suitable amount of water into the sweet material; agitating and gradually raising the temperature to 80-90 DEG C; completely dissolving and keeping the heat for 5-10 minutes; filtering and cooling; adding the taurine, the isoleucine, the valine, the L-carnitine, the leucine, the sodium chloride, monopotassium phosphate, the calcium lactate and the magnesium sulfate into the pure water; completely dissolving and filtering; mixing the two solutions and mixing uniformly; adding the essence and agitating uniformly; carrying out super-high-temperature instant sterilization; filling, sealing and cooling to obtain a finished product. The product prepared by the method can be used for adjusting the body fluid equilibrium and also has the obvious effects of delaying the occurrence of fatigues and promoting the fatigue recovery.