Abstract: During the large-scale application of nitrogen-fixing blue-green algal mixture in the late rice cultivation, we have developed a series of methods for mass cultivation and production of algal inoculum, including the cultivation in the algal nursery bed in the field, and open air mass culture of algae in the resting field between the two crops. By these procedures, more than 30 tons of algal inoculum had been produeed and were introduced into the late rice field. After strengthened management, 990 mu of late rice fields of Xianfeng Production Brigade were fully algalized. The inoculated fields showed exuberant algal growth and no less than 500 kg of algae (fresh weight) per mu was found. Estimated by random sampling, the establishment of nitrogen-fixing blue-green algae in the inoculated rice fields amounted to about 500 tons.The algalization of the late rice cultivation made an average increase of about 10% in the grain yield, individually more than 20%, as compared with the control.Therefore, it is possible that the algalization of the late rice field by inoculation of nitrogen-fixing blue-green aglae has good prospects as a new resource of supplement fertilizer for the late rice cultivation.