Abstract: Single factor design and quadratic orthogonal design test were conducted to study the interaction effect of nitrogen fertilizer and density on yield, dry matter and yield components of super rice‘Longjing 31’ in cold region. The results indicated that the yield had a quadratic curve relationship with nitrogen fertilizer and density, at the same time, interaction effect of nitrogen fertilizer and density on yield was significant, and it was easier to achieve the goal of high yield with middle level nitrogen fertilizer and high level density. The experiments obtained the maximum yield (9948.17 kg/hm2) when nitrogen fertilizer was 135.0 kg/hm2 and density was 34.6 points/m2. Dry matter weight in full heading stage was the heaviest with high level nitrogen fertilizer and high level density, but the yield was significantly reduced. It was easier to achieve more panicles with high level nitrogen fertilizer and high level density. It was easier to achieve bigger panicles with middle level nitrogen fertilizer and low level density. There was no interaction relationship between 1000-grain weight and nitrogen fertilizer and density. Therefore, it could build a reasonable population structure to obtain the appropriate dry matter weight in full heading stage with reasonable nitrogen fertilizer and density, in order to play the yield potential of super rice.