The invention discloses a water supplementing-type bath lotion and a preparation method thereof. The water supplementing-type bath lotion comprises the following raw materials by percentage: 2-7% of lauric acid, 5-8% of myristic acid, 0.5-1.5% of stearic acid, 2-5% of potassium hydroxide, 6-12% of a cocamidopropyl MIPA thickening agent, 0.5-1.5% of coconut oil acylglycine salt, 5-10% of glycerin,70-60% of water, 0.2-1% of an antiseptic, and 1-3% of aloe, tea and Chinese ilex bark extracts. By adding an aloe extract, microbial fermentation is used for biological extraction, the aloe extract isbenefit for skin pore convergence, and is capable of smoothing the skin, magnetic water is used during an extraction process, active factors of the skin is increased, water supplementing effect is enhanced, water retention performance is increased, skin absorption is convenient, coconut oil acylglycine salt can effectively improve the system foams, the steps of drying, crushing, and sieving filtering are carried out on the tea and Chinese ilex bark, and the anticorrosion performance of the bath lotion is increased.