The invention discloses mangiferin aglycone crystal form I. X-ray powder diffraction analysis, DSC analysis, TG-DTA analysis, IR analysis and HPLC analysis show that mangiferin aglycone crystal form I is a new crystal form. Mangiferin aglycone crystal form I in comparison with existing mangiferin aglycone has high purity, high stability in light, humidity and heat, high bioavailability. The invention also provides preparation method of mangiferin aglycone crystal form I, pharmaceutical composition and dosage form comprising the same.
