Soil erosion which easily progresses due to heavy rain in the tropical climate is a serious issue for mined-land reclamation in Indonesia since it causes plant death. Moreover, acidifi-cation of soils occurs because of sulfide minerals in mining area. The physical properties of soils are changed by the acidification of soils according to previous studies. Thus, since the erosion rate of soils greatly depends on physical characteristics of soils, the relation between the change of physical properties of soils caused by soil acidification and soil erosion has to be considered for erosion control in mining area. In this study, physical properties of the soil samples in which the soil-pH was adjusted with H2SO4 were measured, followed by the artificial rainfall test with the samples in order to understand the effect of acidification of soils on erosion rate. The results showed that the decrease of cohesive strength among soil particles caused by the decline of consistency limit with soil acidification resulted in the increase of erosion rate. Hence, soil acidi-fication should also be prevented with the measures against soil erosion for successful mined-land reclamation. Based on DPSIR model and considered previous studies and realities, this essay chooses a typical case, Wu’an, in order to build an ecological security evaluation system. With reference to relevant standards, eco-logical security level was determined. There is a want of developmental driver of urban system, pressure of habitat overload and obviously insufficient social response. In order to get out of “resource curse”, Wu’an should make the innovation-driven improvement and increase the investment in environmental protection.