The application value of three way cross for hybrid rice breeding was studied by using an indica second cytoplasm-genetic male sterile lines(CMS)9730A. It was based on the analysis of the pollen fertility, self bred rate, female fertility, sensitivity to GA_3, out rate of chapiter, bloom time, restoration of male sterile of 9730A, and the variation analysis of heading, plant height, effective panicles, grain yield per plant, seed set rate, panicle length of main culm, flag leaf length of main culm, spikelets per panicle of three cross hybrid. The results indicated that through using the second maintainer of male sterile lines which had different good agronomy characters, the cultivars derived from the traditional breeding methods could be made a good use of the hybrid rice breeding program, and the second CMS lines with better floral characteristics could be obtained. With the second CMS lines ,we could improve the yield level of the hybrid seeds production, and combine the various good agronomy characters to hybrid rice cultivars with keeping their main agronomy traits in the same time.