Due to high moisture content, complicated composition and circumstances, the conservation of earthen sites under conditions of high moisture is one of the most difficult problems in cultural heritage protection. Therefore research on utility of reinforcement materials and portfolio optimization are of practical significance. Based on the existing research and cases, three protective materials were chosen as strengthening agents, and a series of indoor and field tests were carried out and are described in this paper. The strengthening effects of different proportions of the strengthening agents and select the optimum performance indicators, such as morphology,penetration depth,strength and collapse resistance were compared. The tests show that using the chosen strengthening agents and the proper proportions can give good reinforcement effects, such as improve resistance to pulverization and inhibition of the growth of fungi. Furthermore, it can significantly improve the unconfined compressive and shear strength of soil specimens when the moisture content is low. Therefore the results of the studies can be applied to the consolidation and conservation of earthen sites under moisture conditions.