For the purpose of foam dyeing; the stability of foam was investigated at different blow ratio and concentration of stabilizer, salt, and alkali. As a barometer of foam stability, foam viscosity and volume of drainaged liquid from the foam were measured with time passage. Also, the effect of stabilizer, salt and alkali concentration on blow ratio was examined. The distribution of reactive dye in the foam and the effect of stabilizer, salt and alkali concentration on it were measured as well. For the evenness of foam dyed fabric, the average and deviation of reflectance were measured. It was found that the foam stability was increased under the condition of higher blow ratio or more stabilizer concentration, while was it decreased when salt and/or alkali were added. It was also found that fabric speeds influenced on reflectance of foam dyed fabric and the deviation of reflectance was within 0.6%.