Superhydrophilic/underwater superoleophobic materials are promising for diverse applications including oil/water separation, self-cleaning, anti-fogging, and biomedicine. The integration of different functions, particularly oil resistance and optical transparency, to design superhydrophilic coatings with multifunctionality is still rare and highly desirable. Here, a transparent and multifunctional superhydrophilic coating was prepared by a simple combination of co-deposition and biomineralization strategy. The mineralized coating exhibits high transparency with a light transmission of approximately 90 % and excellent superhydrophilicity with a water contact angle of nearly 0°. The homogeneous nanostructure and strong hydration capabilities of amorphous calcium carbonate endow the coating with outstanding anti-oil-fouling properties. The coated porous membranes could effectively separate various immiscible oil/water mixtures and oil-in-water emulsions due to its excellent resistance to oil fouling. Furthermore, the transparent superhydrophilic coating demonstrates superior anti-fogging capabilities. With its multifunctionality, independent-substrate universality, and straightforward preparation process, this coating has excellent potential for a wide range of practical applications, such as oil spill remediation and underwater optics, particularly in complex operating environments.