Abstract: The similar material made by cement, plaster and sand in certain ratio situation did not disintegrate when they met water, whereas they softened like rock. By the similar material proportion test at different sand-binder ratio and cement-plaster ratio, this paper summarized the changing rules of softening coefficient and water-absorption affected by sand-binder ratio and cement-plaster ratio. The softening coefficient of similar material reduced as the sand-binder increasing whereas ascended as the cement-plaster increasing and the variation range was similar with real rock. The water-absorption of similar material ascended as the sand-binder increasing whereas reduced as the cement-plaster increasing and it was larger than the water-absorption of real rock.