Abstract: A grain boundary enginering (GBE) processing and grain boundary character distributions(GBCD) in the industry brass H68 were studied by means of electron back-scattered diffraction, etc. The results show that the H68 brass was subjected to cold rolling 6% followed by annealing at 923 K for 10 min after solid solution and pretreatment, its special boundary percentage of 76% was obtained, and the size of the ∑3n(n=1, 2, 3)special particle clusters surrounded by general grain bounderies with high angle was larger than 300 μm. The connectivity of general large angle boundaries networks were interrupted by the special boundaries, and the GBCD optimization was realized. It was found out that the formation of incoherent ∑3 grain boundaries and the grain refinement from recrystallization during pretreatment provided conditions for the induction of migration of ∑3n(n=1, 2, 3) grain boundaries during subsequent cold rolled and followed by annealing, which was the main mechanism of GBCD optimization in the brass H68.