The invention discloses bicontinuous-phase thorough cleansing oil and a preparation method thereof, and belongs to the technical field of cosmetics. The cleansing oil is prepared from, by mass, 75-95%of a cosmetic matrix and 5-25% of a surfactant, wherein the cosmetic matrix is prepared from a component A, a component B and a component C, the component A is prepared from 1-10% of alkane (alkene)hydrocarbon grease and 30-80% of ester grease, the component B is prepared from 1-10% of ether grease and 3-15% of vegetable fat, and the component C is prepared from 0.01-1% of an antioxidant, 0-10%of active ingredients and 0.01-0.5% of essence. The prepared bicontinuous-phase thorough cleansing oil can be used even if the hand is wet, a bicontinuous phase is formed after the amount of solubilizing water in the oil is increased, water-phase ingredients and oil-phase ingredients can be uniformly fused, thick makeup does not need to be kneaded, the color makeup fusing speed is high, the cleansing oil can be removed after being smeared slightly, the self-emulsifying capacity is high, the nanoscale emulsification particle size washing performance is good, the pure natural vegetable oil in the formula is moist and moist in skin feeling and not sticky, and therefore the effect of combining makeup removal and skin nourishing is achieved.