In order to investigate the action mechanisms of copper tailing powder in the complex binders pastes, the samples of complex binder with copper tailing powder content up to 15%，30% and 45% were prepared. Influence of different grinding time and curing temperature of copper tailing powder on the compressive strength of complex binder paste were investigated by compressive strength activity index and hydration activity contribution rate. The hydrated product of complex binders pastes were studied by using XRD and SEM. The results show that the compressive strength of complex binder paste decreases with the increasing copper tailing powder content, but the later strength will increase. The hydration activity of copper tailing powder is very low when the content is 45%, and there are many pores in the slurry. Copper tailings do not form new crystal phase in cement slurry until 28d when the activity of copper tailings is activated.The complex binders pastes strength will increase and the later strength growth rate will decrease when the curing temperature and grinding time increased.