Tribocorrosion is often complicated and harmful to metallic components, which depends on the mechanics of the tribological contact, on the electrochemical characters, on the properties of the contacting materials, and on the physico-chemical properties of the environment. In this work, effects of corrosive media on the friction and wear behaviour, on the corrosion behaviour and on the synergistic effect between them were investigated in detail on a pin-on-disc tribometer. Although no electrochemical corrosion occurs in distilled water, its lubricity is so bad that plastic ratchetting effect and abrasive wear are observed on 304SS surface which result in severe material loss. In other three simulated seawater, corrosion and wear interact positively, making the pure mechanical wear and corrosion accelerated wear including abrasion and delamination, be the main reasons for 304SS degradation. Note that solution pH also plays an important role in determining material degradation.