Abstract: In-troduction of nitrogen fixing blue-green algae in rice seedling beds may result in sturdy rice seedlings. After transplantation, the recovering period was earlierised for 1–2 days and the time of effective tillering was prolonged for 1–3 days. As a result, the number of ears, ear length and average grains of each ear all increased. The average yield per mu in the experimental plots of early and late rice were increased by 7.68% and 9.3% respectively. So it is considered that nitrogen fixing blue-green algae as a fertilizer source will be of developmental prospeet.