CrAlSiN with thickness up to 16 µm was deposited on tungsten carbide via multi-deposition process by cathode arc deposition technique. Scratch and water-sand jet impingement erosion tests were carried out to evaluate the adhesion by determining the worn surface of the coatings. Results showed that the failure mode of the adhesion can be concluded that the weak bond of each CrAlSiN layer as compared to the strong bond between the coating and substrate. The average surface roughness of the coatings before the erosion test was about the same level. After the erosion test of 30 minutes, the eroded CrAlSiN coatings exhibited improved average surface roughness as compared to the original CrAlSiN coatings. Further increasing the erosion up to 60 minutes, the wear and minor peeling of the CrAlSiN coating between each layer was observed. A further research to improve the bond strength between each layer was needed.