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The aerodynamic performance of compressor airfoil is significantly affected by the sur-face roughness at low Reynolds number (Re). In the present study, numerical simulations have been conducted to investigate the impact of surface roughness on the profile loss of a high subsonic com-pressor airfoil at Re=1.5 × 105. Four roughness locations, covering 10％, 30％, 50％and 100％of the suction surface from the leading edge and seven roughness magnitudes (Ra) ranging from 52 to 525μm were selected. Results showed that the surface roughness mainly determined the loss gener-ation process by influencing the structure of the Laminar Separation Bubble (LSB) and the turbu-lence level near the wall. For all the roughness locations, the variation trend for the profile loss with the roughness magnitude was similar. In the transitionally rough region, the negative displacement effect of the LSB was suppressed with the increase of roughness magnitude, leading to a maximum decrease of 14.6％, 16.04％, 16.45％ and 10.20％ in the profile loss at Ra=157μm for the four roughness locations, respectively. However, with a further increase of the roughness magnitude in the fully rough region, the stronger turbulent dissipation enhanced the growth rate of the turbu-lent boundary layer and increased the profile loss instead. By comparison, the leading edge rough-ness played a dominant role in the boundary layer development and performance variation. To takefully advantage of the surface roughness reducing profile loss at low Re, the effects of roughness on suppressing LSB and inducing strong turbulent dissipation should be balanced effectively.