The effect of nitrogen ferilizer rate and transplant density on the infectious level of insects and the yield of the ADI 28 rice cultivar was studied in the spring crop 2018 in Dien Chau District, Nghe An Province. Experiment was conducted with 15 treatments and 3 replications, according Split-plot design, including five nitrogen rates 80 and 100kgN/ha of green urea; 80 and 100 kgN/ha of yellow urea and 120 kgN/ha urea; three transplanting densities (31-36-41 clusters/m2). Results indicated that nitrogen rate and transplanting density affected the infectious level of insects and the yield of the ADI 28 rice. Applying low nitrogen and sparse density gave the lowest infectious rate of the insect species C. medinalis and S. incertulas (80kgN/ha of yellow urea, 31 clusters /m2; 80 kgN/ha of green urea, 31 clusters /m2). Using yellow urea or green urea for the ADI 28 rice cultivar showed the better efficiencies than that of white urea. The treatment of 100 kgN/ha of green urea and 36 clusters /m2; 100 kg/ha of yellow urea and 36 clusters/m2 showed the best results.