<p>This study develops the geopolymer-based artificial rock to replicate the transmission and reflection of stress waves in sandstone. Rock-like specimens were prepared with variations in aggregate content (30%, 40%, 50%, and 60%) and iron powder ratio (0%, 20%, 40%, 60%, 80%, and 100%). The density, wave velocity and wave impedance of the specimens were determined based on the density measurement and ultrasonic test. Two optimal mix proportions ranges for artificial rock were identified by comparing the density, wave velocity and wave impedance of rock-like specimens with the those of sandstone. Pendulum impact tests were conducted to validate the ability of the artificial rock to replicate the transmission and reflection coefficients of stress waves in sandstone. The results show that the density, wave velocity and wave impedance of artificial rock with optimal mix proportions closely match those of sandstone, with all relative errors below 3%. The transmission and reflection coefficients of stress waves in the artificial rock deviate by less than 4.64% from those in sandstone at different frequencies. The developed artificial rock can replicate the transmission and reflection characteristics of stress waves in sandstone.</p>