We measured thermal boundary resistance at the organic-inorganic interface to calculate the effective thermal conductivity by changing the thickness of both PEDOT:PSS and Bismuth Telluride in multi-layered thin films. The total thermal resistance of the films as a function of thickness were measured by using a differential 3ω method. organic-inorganic thermal boundary resistance is larger than inorganic-inorganic thermal boundary resistance due to high contrast of mechanical properties between organic and inorganic materials. The measured PEDOT:PSS-Bismuth Telluride thermal boundary resistance was 1.1±0.3×10^-7( m²･K ) / W. The measured high thermal boundary resistance can explain the low value of effective thermal conductivity of organic-inorganic composite film.