Refined methyl, ethyl, propyl, 1-butyl, and 2-butyl biodiesels as well as unrefined methyl biodiesels containing glycerides were prepared, and their solvent power was evaluated by measuring the kauri-butanol value. By analysis of the kauri-butanol values of biodiesels with different fatty acid profiles and different alcohol types, some interesting results were obtained. The pure methyl esters have larger kauri-butanol values than those containing glycerides. The unsaturated fatty acid esters have larger kauri-butanol values than saturated fatty acid esters, while the number of double bonds of the unsaturated fatty acid has little effect on the value. The shorter the carbon chain of the fatty acid group or alcohol group, the larger the kauributanol value of biodiesel. Biodiesel with straight chains has a larger kauri-butanol value than that with branched chains.