Abstract: In order to develop a multi-functional oil-water separation sponge that is rich in raw materials, environmentally friendly, easy to operate in complex environment, and of good reusability, superhydrophobic collagen-based composite sponge (Fe₃O₄/PDMS-COL) was prepared by impregnating collagen sponge with polydimethylsiloxane (PDMS)/ferroferric oxide nanoparticles (Fe₃O₄). The changes of chemical structure and microstructure after modification were characterized, and the oil-water separation performance was studied. According to the measurement of contact angle, when the concentration of collagen (COL) is 10 mg/mL and the concentration of PDMS is 15vol%, the water contact angle of the composite sponge reaches 150.3°. The results from FTIR, XPS, XRD and TG show that Fe₃O₄/PDMS compounds with collagen sponge successfully. FE-SEM observation shows that the addition of Fe₃O₄ nanoparticles construct rough surface structures effectively. Fe₃O₄/PDMS-COL can adsorb a variety of oil phases, including benzene, n-hexane, ethyl acetate, vacuum pump oil, peanut oil, among which the adsorption capacity (47 g/g) toward ethyl acetate is the highest, meanwhile the separation efficiency towards various oil phases reaches no less than 99%. After recycling for 20 times for absorbing benzene, both of the contact angle and magnetism of the sponge do not reduce significantly. Moreover, Fe₃O₄/PDMS-COL has a desirable emulsion separation ability and can effectively separate oil-in-water emulsion. Oil-water separation experiments were carried out in various scenarios under the action of external magnetic field, demonstrating the favourable magnetic responsiveness and manipulation. In addition, Fe₃O₄/PDMS-COL exhibits a good flame retardant performance. Furthermore, Fe₃O₄/PDMS-COL possesses an excellent separation capacity toward solid oil/water system in a complex environment, due to its near infrared photothermal effect.