【Objective】 Guaranteeing the seed purity of photo-thermo-sensitive genic male sterile (PTGMS) lines is extremely important for developing and using two-line hybrids. Problems still remained in existing technologies which put too much emphasis on preventing the threshold temperature drift and neglect maintaining not only high seed purity but authenticity. To solve these problems, a new set of “Six-Nursery Method” purification and multiplication system of PTGMS lines in rice has been established based on years of multiplication practices of PTGMS line Y58S in large scale commercially. 【Method】 Key technologies of this system are as follows: initial separating typical monoclonal in screening nursery which is sampled directly from commercial foundation seeds in mass multiplication, and then genetically purifying critical temperature inducing male sterility in critical temperature identification nursery; integrating evaluation results in 3 nurseries, such as group observation nursery, combining ability identification nursery and outcrossing testing nursery, to the final selection for purified genetic background and uniformed phenotype, in order to screening authentic core lines and to obtaining original seed; establishing a specifical original seed multiplication base to achieve the high purity original seed; multiplying original seed to produce breeder seed and multiplying breeder seed to produce foundation seed of PTGMS lines. 【Conclusion】 Practices have proved that application of such a set of techniques could guarantee stable sterility and identical genetic background of PTGMS line and greatly improve the safety and reliability of two line hybrids in commercial production. Since 2008, 2.49 million kg foundation seeds of Y58S with the purity over 99.5% have been produced by applying this purification and multiplication system, and been provided to seed companies for hybrid seed production, which have produced a large number hybrid seeds for planting 14.74 million hectare in farmer’s field.