This paper studies the distributed controller design for multi-agent systems (MASs) with stochastic upper-triangular nonlinear dynamics under the directed network topology. By developing the distributed low-gain homogeneous domination method, distributed controllers are designed. By using the algebraic graph theory and stochastic analysis method, it can be proved that the followers can achieve mean square bounded output tracking of the leader while keeping all the states of the closed-loop system bounded in probability. Finally, a simulation example is given to illustrate the efficiency of the distributed controllers.