In biomass gasification technology, catalytic reforming of tar with non-natural catalysts is one of the most effective methods to remove by-product tar. This review mainly summarizes the kinetic characteristics, mechanisms, and activities of non-natural catalysts on tar reforming, and the solutions to the above problems. In this paper, the deactivation of catalysts, the influence of catalysts on environment and regeneration methods are introduced in detail, which provides reference for designing efficient, environmentally friendly and sustainable catalysts. In addition, some suggestions about biomass tar reforming catalysts are also put forward. To date, gratifying results have been achieved in the development of non-natural catalysts for tar steam reforming, however, due to the inevitable deactivation of catalysts and the negative impact on the waste catalyst environment, the use of these catalysts is still a long way from the truly efficient and clean biomass tar catalysis. In order to achieve this goal, it is still necessary to design catalysts that are more active, stable, environmentally friendly and economical. We believe this review is conducive to promote the research and development of non-natural catalysts for highly efficient conversion of biomass tar into syngas, which can be used as raw materials for various chemical products, contributing to resource conservation and sustainable development.