Abstract: Y Liangyou 5866 was a new two-line hybrid medium indica combination developed by Yafeng Rice Breeding Research Center in Fuzhou City by crossing between the Photo-thermo-sensitive genic male sterile line Y58S introduced from Hunan Hybrid Rice Research Center and the self-bred indica restorer line Yahui66. This combination has taken part in the regional trial of semilate rice in Fujian Province, and the rice quality reached the standard of three-grade high quality rice variety issued by the ministry of rice quality, showing the characteristics such as suitable ripening stage, large panicle and grains, high ripening rate, good yielding ability and stability, excellent rice quality, wide adaptability, and good colouring at ripening stage, which was approved by Fujian Variety Examination Committee in 2015 (2015001). The breeding process, yield of regional trial, characteristics and high-yield cultivation and seed production technology of Y Liangyou 5866 were introduced in this paper.