A surface roughness measuring system applying laser displacement sensor by a non-contact method is developed. The range of errors incurred by effect of colors is within 5%. In case of dark colors, particularly, error is reduced and on the contrary bright colors have higher possibility of errors. The SMD and heights measured by a non-contact method are increased as hairiness is increased. The difference between FFT analyzed surface roughness spectrum and densities of fabric along the warp and weft directions is within 15%. Laser displacement sensor is useful in measuring surface roughness by a non-contact method.