Geopark Silokek is National Geopark located in Sijunjung Regency, West Sumatera that comprises potential attractiveness for regional as well as national tourism sector. Tourism development in Geopark Silokek has been done since 2004 in order to improve local community economy and reduce environmental dergadation. Tourism development has focused on obtaining the positive impact in economic dimension and tends to ignore the sustainability of environmental and socio-cultural dimensions so far. The aims of this research are to describe changes on tourism development in Geopark Silokek as National Geopark and to examine sustainability of tourism development in Geopark Silokek as tourism destination. The approach used in this research is qualitative. Data were collected through observation, interviews, and document study. Collected data were analyzed by qualitative-descriptive analysis method. The result of this research showed that tourism development in Geopark Silokek as National Geopark change to be better. The condition of tourism at the period before Geopark Silokek legitimated as National Geopark was not optimal while at the period after it is approved as National Geopark the quality getting enhancement, both in terms of attraction, amenities, accessibility, and ancillary. Furthermore, sustainable tourism development has not implemented integrally in the development of Geopark Silokek becoming tourism destination. The tourism development in Geopark Silokek does not show the sustainability in environmental dimension, socio-cultural dimension, nor economic dimension.