In this study, we notice on Alkali metal complex. They are composites from alkali metal salt and ether molecules. These complexes are very fascinate materials because they are one of the functional material. They have ion transportation ability and low vapor pressure etc. Many researches were reported, for example, Li+/Glyme as solvation ionic liquid and Li+/PEG as solid or gel electrolyte for Li+ ion batteries. They form complex between oxygen atom and Li+. However, electronic states about the complex which should reflect strength of coordinate bonding in them did not get clear in detail. We have investigated about changes in electronic transitions of these composite from PEG and Li by forming complex. Using Attenuated total reflectance spectroscopic in Far Ultra-violet region (ATR-FUV), electronic transitions in 140-200nm (FUV) can be observed easily. Electronic states of PEG were already studied by ATR-FUV. PEGs have 3 transitions about n – Rydberg transitions, 153nm, 163nm and 175nm were assigned to n (OH) – 3p Ryd, n (COC) – 3p and n (COC) – 3s Ryd respectively3. In this study, PEG and Lithium Bis (trifluoromethane sulfonyl) imide (LiTFSI) were investigated in wide range of concentration and also used various samples, for example cations (Li+, Na+, K+) and anions (BF4, PF6, NO3-, and trifluoromethane sulfonyl family etc.). Furthermore, simulation spectra from quantum calculation spectra by time dependent-density function theory (TD-DFT, cam-b3lyp/6-311++g (2d, p)) were investigated. Experimental and calculation results were compared to discuss changes in electronic states and these result.