Abstract: Similar material is the key factor to replicate the rock avalanche dam-forming and dam-breaking process in laboratory experiments. Few rock similar materials can be used to model this process at present. Therefore,we choose seven raw materials to prepare similar materials to conduct proportion experiments. These materials include(a) barite and calcium carbonate sand as aggregate,(b)gypsum and sodium silicate as binder,(c)sodium carboxymethyl cellulose,glycerol and water as auxiliary additives. The control variable method is used to study the influence of five factors on the physical and mechanical properties of similar materials. The factors include the ratio of aggregate and binder,the ratio of barite and calcium carbonate sand,the ratio of sodium silicate and gypsum,sodium carboxymethyl cellulose content and water content. The mechanism of sodium silicate controlling the water stability of similar materials is preliminarily explored. The results show that: the ratio of aggregate and binder controls elastic modulus,the ratio of barite and quartz sand has the great effect on the angle of internal friction,the ratio of sodium silicate and gypsum controls water stability,sodium carboxymethyl cellulose controls the angle of internal friction,water content controls cohesion and compressive strength. Sodium silicate plays a role of chemical cementation,filling and skeleton in improving the water stability of materials,which is the key factor to control the water stability of similar materials. Based on the experimental results and theoretical analysis,the similar materials with low strength,and good water stability are prepared. The obtained similar materials can be used to conduct the physical test when the similarity ratio is approximately 1︰400-1︰800.