In order to evaluate the effects of reinforcement of earthen archaeological sites in damp environments, onsite experiments were done to reinforce a simulated archaeological excavation unit in Hangzhou City. The wave velocity, water content, and relative horizontal displacement of a reinforced pit wall after reinforcement were measured. Then the stability of the simulated archaeological excavation unit was evaluated, expecting that of done in a quantitative, scientific way, reference information for assessment of the reinforcement effects could be obtained in other earthen archaeological sites. Experimental results show that the deeper the earth, the higher the water content on the surface of the pit wall; that the initial strength and the hardening process of soil ramming increase as the depth increases;that the strength of ramming soil increases as time goes on; that 4~5 days after reinforcement, the displacement accelerates; and that the deeper in the body, the bigger the displacement.The research results show that deformation monitoring is a useful scientific method to evaluate the stability of the reinforcement. Surface moisture and wave velocity monitoring are reasonable parameters for measuring the strength of rammed earth.