Abstract: To assess quickly the conservation efficacy of nature reserve is of great significance to make scientific management decisions. In this paper, the remote sensing image was first interpreted, in order to accomplish the landscape classification and analyze the landscape dynamic of Ar Horqin Nature Reserve, Inner Mongolia. And then we assessed the conservation efficacy of this nature reserve during the 2004-2014 by using the quality index of protected landscape, interference index of anthropogenic landscape and conservation efficacy index, etc. The results showed that the proportion of natural landscapes in Ar Horqin Nature Reserve, Inner Mongolia increased from 92.2% to 92.8% during 2004-2014, with a significant increase in areas of natural grassland and shrub land, while the areas of lake and river reduced quickly. Meanwhile, the landscape pattern had significantly changed in this nature reserve. The proportions of areas transformed to and from other landscape types were particularly high, and the landscape transformation index was 0.33. Moreover, the protected landscapes in the nature reserve and its various function zones increased obviously in area and proportion, with the quality index of protected landscapes of this nature reserve increased from 24.37 in 2004 to 25.36 in 2014, indicating the quality of protected landscape improved. Nonetheless, each function zone had different degrees of artificial interference in the nature reserve, and the artificial interfered landscapes increased distinctively. The interference index of anthropogenic landscapes was -0.79 and -0.96 in 2004 and 2014 respectively, showing that artificial disturbance intensity was strengthened. On the whole, it was found that the conservation efficacy index of Ar Horqin Nature Reserve, Inner Mongolia was 3.5% during the study period, which achieved a “very good” landscape conservation efficacy, and wildlife habitat tended to be better.