In order to determine the influence of nitrogen on agronomic characters, forage yield and quality, a Cheju Native Danji radish was cultured on the volcanic ash soil at the Experimental Farm of Cheju University under the seven levels of nitrogen rates (0, 50, 100, 150, 200, 250, 300 ㎏/㏊) from April 17 to June 20, 1999. The flowering time was delayed from 52 to 55 days after seeding as the nitrogen rate increased. The plant height increased by increase of nitrogen rate, showing longest at 300 ㎏/㏊ with 93cm and shortest at no application plot with 68㎝. The difference on leaf number and root length by nitrogen rates showed a similar tendency to the plant height. Also total fresh yield, forage and root fresh weight, and forage dry matter were gradually increased by the increase of nitrogen application amount, accordingly the total fresh yield showed the 40.47 MT/㏊ and 83.30 MT/㏊ at 0 and 300 ㎏/㏊ of nitrogen application, respectively. As the nitrogen rate increased from 0 to 300 ㎏/㏊, the content of crude protein and total digestible nutrients significantly increased from 17.1% to 32.2% and from 46.9 to 68.9%, respectively. And the ether extract content and nitrogen free extract content were slightly increased. While the contents of crude ash and crude fiber decreased from 19.7% to 15.8% and from 14.9% to 11.6%, respectively.