Using Xinei S and Zhongqiao A, two small grain recessive CMS lines, as female parent, promoting their flowering with CO2, cross with nine different large grain recovery respectively, and harvest hybrid seeds. Mix hybrid seeds with the seeds of large grain male parent, and separate which by a sieve of particular specification to study the efficiency of separation, aiming to provide theoretical basis and technical parameters for mixed planting and mixed income mechanized seed production techniques of hybrid rice. Meanwhile, the xenia effect of hybrid seeds （F0） and the hybrids vigor of F1 were also be analyzed and compared in this paper. The results showed that there were no obvious xenia effect in the shape of hybrid seeds. After the mixed small grain hybrid seeds and large grain male parent went through the sieve, the purities of hybrid seeds obtained were all over 97.5%, which can meet the need of production. The number of tiller per plant, and the number of filled grains per plant, and the weight per plant were all significantly higher than that of parent, that shows strong hybrids vigor.