Abstract: A group of atomizing nozzls with ring holes for multiple focusing has been designed and pilot atomizing experiments have been made.Results have shown that,as for the fine powder collection rate concerned,the nozzle with double focusing is higher than the one with single focusing,and the nozzle with ternary focusing is higher than the one with double focusing.The nozzle with quartic focusing has optimum result.Under the condition of same pressure,the mean particle size diameter d 50 atomized by the nozzle with quartic focusing decreases to 150μm and that of the nozzle with single focusing is 362μm