Based on idealized non-steady state transient heat conduction model, the thermal conductivities of apple samples were determined at various moisture contents by using a specifically designed apparatus. The apparatus is rapidly, simply, accurately and only has relatively small sample requirement. Experimental data of thermal conductivities of apples showed a tendency of linear increase with the increase of moisture content of apple sample at the same temperature. An empirical correlation model for the thermal conductivity of apple as a function of moisture content was obtained. The developed model can be used to predict the thermal conductivity of apple satisfactorily in the entire range of moisture content. The results can be better contributed to the food engineering application.