Background Preeclampsia (PE) is associated with abnormal fatty acid beta-oxidation (FAO),especially metabolic disorders of long-chain fatty acid oxidation.The role of FAO dysfunction in inadequate invasion is unclear.The aim of this study was to explore the influence of various lengths fatty acids oxidation on invasiveness of trophoblasts.Methods Primary human trophoblast cells and HTR8/SVneo cells were treated with fatty acids of various lengths.Morphological changes,lipid deposition and ultrastructure changes of trophoblast cells were detected.Cells invasiveness was determined by transwell insert.CPT1,CPT2 and long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) protein expression were analyzed.The correlation between intracellular lipid droplets deposition and cells invasiveness was evaluated.Results Cells treated with long-chain fatty acids showed significant increased lipid droplets deposition,severe mitochondrial damage,decreased CPT2 and LCHAD protein expression (P ＜0.05) but no significant difference in CPT1 protein expression (P ＞0.05).Invasiveness of the trophoblast cells of the LC-FFA group significantly decreased (P ＜0.05).Intracellular lipid droplets deposition was negatively correlated with invasivenss (R=-0.745,P ＜0.05).Conclusion Trophoblast cells after stimulation with long chain fatty acids exist fatty acid oxidation disorders,and reduce the ability of trophoblastic invasion.