In order to improve the resistance of titanium alloy on antifouling of halobios, a laser etching technique was used to build micro-structure with different spacing on Ti6Al4V alloy surface. Polymer-based nanocomposites were coated on the micro-structure to build the micro-nano structure for the superhydrophobic surface of Ti6Al4V alloy. The morphology was investigated by optical microscope and scanning electron microscopy. The contact angles and roll angles were measured by contact angle measurement. Sea-site exposure test was conducted to evaluate its antifouling performance. The results show that the Ti6Al4V alloy surface with a single micro structure is hydrophobic. The contact angles increase with spacing decreasing. When the spacing is 50 μm, the contact angle is as high as 131.8°. But the roll angle is large. Even if the surface is placed vertically or invert, the droplet does not roll. The Ti6Al4V alloy surface with the micro-nano structure is superhydrophobic. The contact angles increase and the roll angles decrease with the spacing decreasing. When the spacing is 50 μm, the contact angle is as high as 163.8°, while the roll angle is only 1.89°. The antifouling performance of superhydrophobic surface with micro-nano structure is significantly superior to that of polishing surface and the surface with a single micro structure