Abstract: Progesterone is one of the most important gonadal hormone in human beings because it is very meaningful to maintain female physiological characteristics and normal physiologic function. Serum progesterone assays are ordinary analysis in clinical laboratory which is required high accuracy. Since the concentration of serum progesterone is in a very low level, immunoassays are routinely used to measure progesterone in clinical practice. The results of these methods are not intrinsically reliable which can in part be explained by cross-reactivity, reagent and so on. To solve these problems, we should establish a reference system of serum progesterone analysis. Two reference measurements procedure had been developed which based on isotope dilution gas chromatography-mass spectrometry. To develop our country’s serum progesterone reference system is an important task for us.