Abstract: β Zeolite supported molybdenum carbide catalyst has been prepared by temperature programmed reduction with n-pentane as a source of carburization, and characterized by XRD. The influences of reaction temperature, pressure, space velocity and the ratio of hydrogen to hydrocarbon on the catalytic performance for hydroisomerization over βMo2C/β zelite have been investigated in a fixedbed downflow reactor using n-heptane as a model reactant. The optimum conditions for the isomerization of n-heptane were 270℃～275℃, 1.0MPa～1.5MPa, LHSV 1.0h－1and the hydrogen to hydrocarbon ratio (Volume Ratio) 200∶1. The results of the reaction showed that the selectivity and yield of isomers reached to 71% and 58%, respectively, with the n-heptane conversion of 82% in the optimum conditions.