Abstract: 【Objective】In order to provide a theoretical basis for the regulation of fruit development in oil palm, the changes of inclusion contents and antioxidant activities during oil palm growth were studied.【Method】Oil palm pistil or fruit at different developmental periods(pistil and pollination for 1-5 months, marked as 0M, 1M-5M) were selected, fruit weight, fruit length, fruit width, oil content, sugar content, soluble protein content, activities of hydrogen peroxide(H₂O₂), superoxide dismutase(SOD), malic dehydrogenase(MDH), glutathione reductase(GR), catalase(CAT) and peroxidase(POD) in the mesocarp of oil palm were measured. The change rule of each index and the correlation between the inclusions contents and the activities of antioxidant enzymes were analyzed.【Result】The fruit grew rapidly 2 months after pollination and stopped at the 5^th month. The lignin began to deposit one month after pollination and stopped at fruit ripening. The oil content of fruit increased slowly in the early stages of fruit development, but increased rapidly in the later stages, and oil content reached 46.02% finally;the total sugar content was higher(92.69 mg/g) in the early stage after pollination, and then decreased rapidly and remained unchanged. The protein concentration increased first and then decreased to the level(0.18 g/L) when the female flower was not pollinated;the hydrogen peroxide content decreased sharply and then maintained a lower level, reached the highest level(1582.44 mmol/g prot) at 0M stage. SOD activity firstly decreased and then increased, reached the highest level(589.43 U/mg prot) at 0M stage;MDH activity firstly remained unchanged and then increased sharply, reached the highest level(4.71 U/mg prot) at 4M stage;GR activity first increased and then decreased, reached the highest level(0.0051 U/g prot) at 1M stage;CAT activity showed wave band change, reached the highest level(59.72 U/mg prot) at 4M stage;POD activity first decreased and then increased, reached the highest level(287.94 U/mg prot) at 5M stage. There was extremely significant positive correlation between total sugar content and H₂O₂content(P<0.01, the same below), there was extremely significant negative correlation between soluble protein content and total SOD activity, and extremely significant positive correlation between fruit weight and fruit size.【Conclusion】During oil palm fruit development, high sugar and protein content in the early stage may contribute to the accumulation of oil and lignin in the later stage, the activities of MDH and GR can be used as one of the indexes to judge the fruit growth and development.