Abstract: 1. Unfertile flowers and low fruiting ratio are the important sources for low yield of C. Oleifera. The cause of low fruit ratio are to be found as following. (1) Dates of onset of blossoming period are not unified even in the same stand. (2) Date of blossoming in period is too late. (3) The existence of sterility plants.2. The fruiting ratio is affected by the characteristics of material parent, but difference in mating compatibility still exists. It follows that only pay attention to the characteristics of material parent, at primary selection, can not greatly influence yield.3. There is no selection particularity of fruitful plants to the pollens of male parent. Therefore, high yield is always obtained no matter what pollens of male parent mated with.4. There are some successive low yield plants with low fruiting ratio in the C. Oleifera population. They always gains lowest yield no matter what pollens of male parent, they mated with. It is considered that the low yields of this type of plants due to their poor heredity and fertility.5. Rainfall during the blossoming period greatly influences the yield of C. Oleifera fruit. Less raindays and lowe Precipitation of florescence then normal year will bring higher yield, while heavy rainfall cause lower production.6. The yield of C. oleifera is related to the date of onset of blossoming period. Plants with full florescence before early frost yield 2.9 times as those after early frost.