Physical similarity model testing is a commonly used method for analyzing the stability of landslide hazards, with the characteristics of similar materials being a crucial factor affecting the feasibility of the experiments. Taking the Fanlingqian landslide in the Laoshan Scenic Area of Qingdao as research background, aiming to develop similar materials suiTable for physical model tests of completely weathered granite landslides. Sand-to-weight ratio, calcium carbonate powder content, bentonite content, and clay content were selected as influencing factors. Using the controlled variable method, 16 groups of similar materials for completely weathered granite landslides were prepared, and indoor experiments were conducted. Sensitivity analyses of cohesion, internal friction angle, permeability coefficient, and compressive strength were performed using range analysis and standard deviation. The results show that the primary factors influencing cohesion are clay content and calcium carbonate powder content. Internal friction angle is primarily influenced by clay content. Uniaxial compressive strength is mainly affected by the sand-to-weight ratio, and all four factors have some influence on the permeability coefficient. Regression analysis was performed to establish a system of multiple linear equations describing the relationships between the four influencing factors and the physical-mechanical properties of the materials. The applicability of the equations for preparing similar materials was verified by comparing them with in-situ materials. The research results provide a theoretical reference for the rapid preparation of similar materials for physical model tests of completely weathered granite landslides.