GLC films are widely applied in the friction and wear fields due to their low friction coefficients and wear rates but they do not perform well in humid environment. Many researchers add Si element to GLC films to saturate sp2 bonds and improve the tribological properties especially in humid environment. However, it should be noticed that there are few studies which focus on the coupling between mechanical damages and corrosion damages of GLC films in marine engineering. The tribological properties of GLC films after corrosion should be considered because there are complex chemical reactions occurring on the surface in marine environment and the chemical components will be changed. In this work, Si-GLC films with different Si contents were prepared by magnetron sputtering technique (Teer CF-800) in order to improve the environmental suitability of GLC films applied in marine engineering. SEM (FEI Quanta FEG 250, equipped with Oxford EDS) and Raman spectrometer (Renishawin Via Reflex) were employed to observe the morphologies, composition and structures of the films. It was found that with the Si content increasing, the films would contain more sp3. "Pseudo multilayer" structure composed of Si-rich layers and C-rich layers was found in compact Si-GLC films due to the limitation of preparation technology and it would affect the mechanical properties of GLC films. The mechanical properties of Si-GLC films were tested by nanoindentation (MTS G200) and wear tester (UMT-3). Notably, environmental tests were conducted before the friction tests to simulate the marine environment. Seawater mist and high-low temperature cycles tests were carried out to evaluate the anti-corrosion properties of the Si-GLC films. It was found that the hardness and elastic modulus of the films reached the maximum value when Si content was 64.51wt.%, which were 21.3 GPa and 245.9 GPa, respectively. Meanwhile, the films with higher Si content performed better in seawater mist and high-low temperature cycle tests, showing the better adaptability to marine environment. According to the results of friction tests, the Si-GLC films with 64.51wt.% Si content had up-and-down friction curves which could be attributed to the "Pseudo multilayer" structure. The Si-rich layers were too thick to maintain a stable friction coefficient. Furthermore, Si-GLC film with 48.11wt.% Si content exhibited the best tribological properties (the lowest and most stable friction coefficient of about 0.1) under different experimental conditions which proved that adding moderate Si into GLC film could stabilize the sp2 structure, avoid graphitization during friction and improve the wear resistance of the film. In general, different contents of Si element are added to hydrogen-free GLC films to modify the tribological and corrosion behaviors in marine engineering. It is found that the hardness increases with the Si content increasing. The Si-GLC films with the highest Si content have the best anti-corrosion property in seawater mist and high-low temperature cycle tests. However, excessive Si content will lead to the erratic friction coefficient due to the "Pseudo multilayer" structure induced by the specific preparation technique. It is found that Si-GLC film with 48.11wt.% Si content exhibits the best tribological properties before and after environmental tests. This work considers the coupling effect between mechanical damages and corrosion damages and can promote the marine application of GLC films.