Blast erosion properties of Plasma sprayed coatings, HVOF sprayed coatings were assessed by using four kinds of erosion-resistant materials. The results obtained are followings. (1)Blast erosion properties of the Plasma sprayed coatings are worse than those of SS400 base metals. (2)Ripple pattern is formed on the eroded area of the surfaces of SS400 base metal and HVOF sprayed coatings. On the other hand, thin sheets are piled up on the eroded area of the surface of the Plasma sprayed coating. (3)The erosion mechanism of the HVOF sprayed coatings is thought to be scratch erosion by shear stress of the erodent. On the other hand, the mechanism of erosion of the Plasma sprayed coatings containing large amount of porosities and microcracks are, is thought to be the separation and omission of thin sheets.