At damp earthen sites, groundwater and rainwater infiltration are the main causes of damage, which can easily lead to the softening and collapse of soil, as well as the growth of mildew and weeds, etc. The same problems were encountered in connection with the protection of an Eastern Zhou sacrificial horse pit site in Linzi District of Zibo, Shandong province. Initially, in order to control the dampness and resulting decay of horse bones caused by water, chemical waterproofing and chemical reinforcement measures were used; however, the problems were not solved. Subsequently, a method of setting an arch in the lower excavation was adopted, and it successfully controlled the influence of groundwater and rainwater. After 30 years of practice, this method has proved reliable. This paper introduces and summarizes the application of the arch bond method for the protection of sacrificial horse pits, and hopefully could provide a reference for similar work in the future.