Abstract: As a typical saturated bicyclic compound, decalin is normally used as a probe molecule of saturated cycloalkanes for the mechanism study of selective ring-opening reaction during the hydrogenation of light cycle oil. In this review, the molecular structure and reaction characteristics of cis-decalin and trans-decalin are introduced. The mechanism of the selective ring-opening reaction of decalin based on different catalytic systems is systematically analyzed, including the carbocation mechanism on monofunctional acid catalysts, the hydrogenolysis reaction mechanism on monofunctional metal catalysts, and the bifunctional ring-opening reaction mechanism on acid-metal bifunctional catalysts. In addition, the effect of the process conditions, such as reaction temperature, support acidity and zeolite pore size, on the performance of selective ring-opening reaction of decalin are summarized. Finally, the shortcomings of current research are put forward, and the urgent and deserved research topics are proposed.