Objective To explore the effects of Xingpi Jieyu Fang ( XPJYF，Spleen- invigorating Depression- relieving Formula) on behaviors and mitochondria ultrastructure of hippocampus neurons and skeletal muscle in depressed rats． Methods Wister rats were randomly divided into five groups: blank control group，model group，sertraline group，XPJYF high- dose and low- dose groups． Chronic unpredictable stress ( CUS) was applied to establish depression models in rats for 28 days． Intragastric gavage was used to offer corresponding medication in treatment groups or distilled water in model and blank control groups． Weight change，sugar /water preference test and open- field test were used to evaluate depressive behavior in rats． Changes in ultrastructure of mitochondria in hippocampus neurons and skeletal muscles of depressive rats were measured by using transmission- electron microscope．Ｒesults Compared with the blank control group，weight gain in model group rats was significantly slowed while the sugar /water preference rate and total moving distance of open- field test decreased significantly ( P 0. 01) ． The number of mitochondria in hippocampal neurons and skeletal muscle in the model group was also reduced with irregular swelling，fractured and fuzzy cristae as well as vacuolar br / 
degeneration． under the transmission- electron microscope Compared with the model group，body weight，total sugar /water preference rate，and total moving distanceof open- field test in XPJYF high- dose，low-dose group and sertraline group were significantly increased ( P 0． 01 ) ． No swelling or vacuolar degeneration were observed in mitochondria of hippocampal neurons and skeletal muscle in XPJYF high-dose group，which were close to the normal level． Hippocampal neuron and skeletal muscle mitochondria of XPJYF low- dose group and sertraline group were slightly swollen with partly fractured and fuzzy cristae． Conclusion The mitochondria structure of hippocampal neurons and skeletal muscle were damaged in depression induced by chronic stress，which may be a key factor in severe fatigue and symptoms involving multiple systems． Xingpi Jieyu formula could improve depressive behavior and mitochondria structure damage in depressed rats． To some extent，the effects of high- dose Xingpi Jieyu formula were better than sertraline in improving depression of rats．