A rock excavation method using an abrasive waterjet (AWJ) system has been developed for efficient construction of tunnels and underground spaces. This rock excavation system using an abrasive waterjet has a considerable competitive edge over conventional rock excavation methods. However, high abrasive consumption is an obstacle to using AWJ for rock excavation. To achieve economic excavation and construction, the expense of abrasives should be minimized by using recycled abrasives. In this study, basic experimental tests were performed to evaluate the cutting performance with a recycled garnet abrasive. Based on the test data, recycling reusability of garnet was analyzed. These basic experimental results can be effectively utilized as baseline data for rock excavation methods using AWJ systems in various types of construction location.