The crystal of Tenaciss igenin with component C21H32O5 belongs to mono-clinic system. The space group is C22—P21. The crystal parameters are as follows: α=10.437?,b=12.467?,c=7.548?,β=109°57′, and of molecules number in an unit cell Z=2. The diffraction data were collected using pw-1100 four-circle diffractometer, the number of independent diffraction data amounts to 1770. The crystal structure was determined by direct method. Refinement of structure parameters was acheived by least-squares method, R= 0.098.The tenaciss igenin is steroid. B-ring and C-ring, C-ring and D-ring all exhibit cisforms. Between the molecules there exist bi-orientation hydrogen-bonds.