Some theory produced in developed countries holds that,the effects of interactive learning by firms within the cluster will increase with the personnel flow and knowledge communication among them.With the comparative analysis of two aluminium material industry clusters that in different development stages in Linqu and Dali,the paper discusses the technology diffusion in cluster.The result shows the opposing viewpoints of current cluster theory.Linqu,which is in the early development stage of cluster,has distinct technology study effect of inner cluster,while it's inconspicuous in the relatively developed industries of Dali.The reason is that the mutual study of different industries is not for technological breakthrough,but for technology imitation and pursuit.It is just this kind of industrial character has decided the applicability of S diffusion curve in the clusters of developing countries.Therefore,the technology diffusion process of inner cluster should be an important viewpoint of understanding the formation of cluster.