Basalt CO2 sequestration, as one form of geological carbon sink, is an economical, safe, and long-lasting method for carbon capture and storage, gaining increasing attention from the international community. Based on the principle of stereology, this study performed morphological processing on SEM-EDX images of basalt from the Eastern Snake River Plain in western Idaho, USA, and used the k-means algorithm to calculate the reactive surface area (RSA) of minerals. Using the obtained RSA, the rate of water-rock reaction with CO2 under different temperature and pressure conditions was calculated. The results indicate that an increased depth of CO2 burial correlates with a higher carbon sequestration efficiency. This study has significant implications for the promotion and assessment of basalt carbon sequestration.