[Objective] To investigate the effects of panicle number,grain number and grain weight on yield under different production conditions. [Method]The yield and its constructions factors of Japonica variety of‘Tongjing 981'under different density and different fertilization level was studied through regression and correlation and path. [Result]The results showed that the panicle number and the grains number and the grain wight can rise yield very significantly. And its yield increase effect from big to small wa...