The experiments were carried out under solution and pot cultural conditions with rice Yang-dao6. Effect of nitrogen on hull size, weight and plumpness and its relationship with plant nutrition were analysed. On comparison with no fertilization, low N application concentration from transplanting to heading, or employing basal fertilizer or tiller promoting one would result in increment of hull size and weight, while raising N application concentration from transplanting to heading or employing excessive spike fertilizer would result in smaller, lighter hull and poorer hull plumpness. The more amount of nitrogen applied, the The experiments were carried out under solution and pot cultural conditions with rice Yang-dao6. Effect of nitrogen on hull size, weight and plumpness and its relationship with plant nutrition were analysed. On comparison with no fertilization, low N application concentration from transplanting to heading , or employing basal fertilizer or tiller promoting one would result in increment of hull size and weight, while raising N application concentration from transplanting to heading or employing excessive spike fertilizer would result in smaller, lighter hull and poorer hull plumpness. The more amount of nitrogen applied, the