The dynamic expression of one cytochrom P450-like gene in mesocarp of oil palm (Elaeis guineensis) nut at five different development stages were analyzed.The content of fatty acid in mesocarp tissues was investigated with chloroform-methanol method.The results showed that mRNA level of the P450-like gene was the highest at the fourth period with 201.07 times of the first stage.The ratio of fatty acid accumulation reached the maximum during the 3rd-4th stage (15.79%).The change of fatty acid accumulation during five stages fitted well with P450 gene expression.According to previous studies,the expression of P450 in the development of oil palm nuts may affect the oxidation,epoxidation or alkylation of fatty acid in oil palm.This study will provide a basis for further research about the regulation of P450 gene during the maturation of oil palm,and open up a new field of modifying oil palm fatty acid metabolism pathway by genetic improvement.