Abstract: Analysis on data of yield and its related factors from two hybrid strains of rice with different sowing dates showed that there was a very significant and positive correlation between grain weight per plant and panicles per plant，spikelets per panicle，seed setting per-centage and 1000 kernel weight．Among those yield-related factors，seed setting percentage produced a strongest effect on grain weight per plant．The effects of sowing dates on phenotype value of grain weight per plant，seed setting rate and path coefficients of seed setting rate were more efective than those on partial correlation coefficients between grain weightper plant and panicles per plaht, total spikelets per panicle and seed setting rate．