This paper discusses the distributed tracking control of the multi-agent systems with an active leader,with measurement noises as the constraint.It is assumed that the followers have known the velocity information ofthe leader but only some followers can directly obtain the output information of the leader and that all followers knownothing about the initial information of the leader.It is also assumed that the measurements of errors among agentsare not accurate due to the noise impact.In this case,it is proved that all followers can track the active leaderaccording to the mean square by means of the conventional protocol,which considers both the fixed topology andthe switching topology.Moreover,the ranges of parameters are given.It is thus concluded that the conventionalprotocol is robust against the measurement noises which are dependent on relative-states.Finally,simulations arecarried out,and the results are consistent with the theoretical ones.