For the output-feedback control of a class of upper-triangular stochastic nonlinear systems, by using backstepping design method, a stabilizing output feedback controller is designed for its corresponding nominal system. Then by using the low gain homogeneous domination technique, an output-feedback controller is constructed for the whole system to ensure that the equilibrium at the origin of the closed-loop system is globally asymptotically stable in probability. The low gain homogeneous domination technique is generalized to stochastic systems, which can solve the stabilization problem for a class of upper-triangular stochastic nonlinear systems for the first time. Finally, a simulation example shows the effectiveness of the control scheme.