Despite the vast potential for the depolymerization of kraft lignin in supercritical systems, selective access to desired renewable products remains a very challenging target. Catalytic depolymerization of kraft lignin was carried out in an isopropanol-water mixture system over a Rh/La2O3/CeO2-ZrO2 catalyst. The H-2 selectivity was adjusted by changing the proportions of isopropanol and water. The introduction of formic acid was more helpful to extend the selectivity range. A correlation was established between liquid product distribution and H-2 selectivity. It was used for predicting the composition of the liquid oil by H-2 selectivity or, optionally, for converting kraft lignin to the desired liquid products. This correlation was applicable to different solvents, temperatures, and catalysts.