Abstract: X-ray diffraction studies on the configuration of 2ξ, 17α-diethynyl-2ξ, 17β-dihydroxy-A-nor-5α-androstane "α-epimer" that possessed antifertility effect and estrogen activity were reported Pure α-epimer was obtained by recrystallization and low pressure silica gel column chromatography combined with HPLC method. Its structure was identified by IR, MS, ¹HNMR. The configuration was determined by single crystal X-ray diffraction analysis. The crystal of α-epimer belonged to orthorhombic, the space group was P222,, with the following crystallographic parameters: a=6.777 (2), b = 12.125 (4), c =25.292 (8),V=2078.5 (1. 2)³, Z=4. One thousand two hundred and thirty-five independent reflections with Ⅰ≥3σ (Ⅰ)were collected on a Nicolet R3M/E four-circle diffractometer by means of MoK α radiation. The structure was solved by direct method and refined by least square technique to a final discrepancy factor of R = 0.039. The molecule was shown to consist of the α-configuration of C₂ and C₁₇ ethynyl groups.The absolute configuration was deduced by the absolute configuration of synthetic raw material, conformation analysis and the study of ¹HNMR. The absolute configuration of asymmetric centers were 2R, 5S, 8R,9S, 10S, 13S ,14S,17R.