X-Ray absorption and diffraction have been used to study a Langmuir-Blodgett film of an iodine-intercalated charge transfer (CT) salt based on EDT-TTF(SC18)2. The polarized X-ray absorption near-edge structure (XANES) of I3- exhibits a strong angular dependence of the 2s-5p(sigma*) resonance intensity. To obtain precise information about the I3- orientation, the observed polarization dependence is compared with the theoretical calculation. It is shown that the I3- molecular axes are distributed randomly in a plane parallel to the substrate. From the viewpoint of the I3- distribution, the effect of annealing is also investigated with polarized XANES spectroscopy and X-ray diffraction. It is confirmed that an annealing process is necessary to achieve a well-stabilized and highly conducting film of the present CT salt. In addition, a possible molecular assembly of this annealed purple phase is proposed via a simulation of the X-ray diffraction profile based on the XANES results.