Abstract: A comparative experimental study on desulphurization of hot iron with nickel by injecting powder through slot porous plug fixed at the bottom of ladle and a usual overhead injecting technology was carried out in an industrial 20 tones ladle. The results showed that when the consumption of calcium carbide powder is 4 kg/t, the desulphurization ratio of the bottom powder injection is 81%~90%, and the heat loss is 23~36°C; the desulphurization ratio of overhead powder injection is 59%~73% and the heat loss is 45~70°C. Although the difference of injecting time between them can be neglected, the total processing time of bottom injection technology is 5 min shorter than that of top injection technology. Therefore, compared with the other desulphurization technologies, the technology of injecting powder with the bottom position has a number of advantages, such as, the higher desulphurization efficiency, the less heat loss and the short recycle time.