This study investigates the effects of equivalent ratios on the combustion and flow characteristics of hydrogen/air in a jet-stabilized combustor using numerical methods. The realizable k - epsilon model is used to describe turbulence flow whereas the FR/ED model is used for chemical reactions. The results show that the vortex structure changes from a single vortex pair to double vortex pairs with a decrease in the equivalent ratio, and the right-side vortexes gradually extrude the left-side vortexes. When the equivalent ratio Phi is 1 and 0.554, the high temperature area is mainly distributed downstream of the air jet hole. As the equivalent ratio further decreases, the high temperature region shrinks sharply and moves up to the vortex area in the range of x <0.06m. The outlet temperature distribution factor (OTDF) initially increases and then decreases with a decrease in the equivalent ratio, however the OTDF is lower than 0.033 at all operating conditions. Similarly, at a small equivalent ratio (0.3693, 0.2216, 0.1583), the mixing and combustion of hydrogen and air mainly occur in range of x < 0.06m, thus achieving flame stabilization in the air backflow region. Complete combustion can be achieved except for the case of Phi = 1 with a combustion efficiency lower than 65%. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.