Transparent soil technology provides an effective means for visual monitoring of internal deformation and seepage within a soil mass. Fully understanding the influencing factors of transparency is the basis for the development of this technology and the premise for realizing the visualization of slurry diffusion of grouting. The transparent soil was prepared with fused quartz particles and mixed mineral oil, by adjusting the ratio of different mineral oil, the particle size of fused quartz and the ambient temperature. Then, the transparent sand with similar gradation to standard sand was prepared to compare the basic physical and mechanical properties of these two materials, after which the grouting model test of large-size transparent sand was carried out. The results show that the ratio of different mineral oil and the particle size of fused quartz have significant influence on the transparency of transparent sand; the refractive index of mixed mineral oil is sensitive to temperature, which decreases with the increase of temperature. In addition, the transparent sand prepared by fused quartz particles with similar gradation to standard sand is highly transparent and its physical and mechanical properties are similar to standard sand. The transparent sand makes the visualization of slurry diffusion process possible in grouting model test. The research results can provide a referencee for promoting the development of transparent soil technology and its application to grouting model test.