Endocannabinoids,endocannabinoid receptors and endocannabinoids hydrolyzing enzymes are three main elements of the endocannabinoid system.The imbalance of this system causes numerous diseases of center nervous system and immune system.The levels of endocannabinoids are the major parameters of the endocannabinoid system activity.An in-depth research of the metabolic pathways of the endocannabinoids is essential to unravel the endocannabinoid system's role in physiological and pathological situations and to devise new therapeutic drugs based on the endocannabinoid system.The present article reviews the advanced progress in the biosynthesis,signal transduction and degradation of the endocannabinoids