In this work, CrZr-Si-N films with various Si contents (<= 6.4 at. %) were synthesized by closed field unbalanced magnetron sputtering with vertical magnetron sources. The characteristics such as hardness, surface morphology, and friction coefficient of the films as a function of the Si content after annealing up to 500 degrees C in air were evaluated. Results revealed that the as-deposited films showed very similar characteristics irrespective of the Si content. However, after annealing at 500 degrees C, the film characteristics showed a strong dependency upon the Si content. After annealing at 500 degrees C, the hardness of the Cr39.4Zr12.3N48.3 film decreased significantly to approximately 24 GPa and the surface roughness value increased approximately 3.5 times more than that of the as-deposited film. The Cr34.6Zr10.6-Si-6.4-N-48.4 film, however, was observed to have a hardness of approximately 30 GPa, which is close to that of the as-deposited film, 32 GPa. In addition, as the wear test temperature increased from room temperature to 500 degrees C, the average friction coefficient of the Cr39.4Zr12.3N48.3 film increased significantly from approximately 0.23 to 0.81, but the average friction coefficient of the Cr34.6Zr10.6-Si-6.4-N-48.4 film was not changed extensively, measuring approximately 0.43. These results could be attributed to the improvement of the thermal stability by adding Si into the Cr-Zr-N films.