The convergence speed in the distributed consensus of integrators over both cooperative and competitive undirected networks is investigated in this paper.It has been well known that as long as the (δ,T) connectivity condition is satisfied,exponential convergence of the consensus can be attained.We further show that,for a cooperative network,increasing the coupling strength can improve the convergence speed.The lower bound of the convergence is also explicitly specified with respect to the coupling strength.Based on this,in the competitive network,the convergence of consensus can be guaranteed by strong cooperative couplings dominating the competitive ones.The results of this paper are established by means of a uniformly completely observable theory.We also show that it is possible to reconstruct the consensus error at a certain time instant from the observations of the past relative state information over a fixed length interval.